[HOTFIX]: Fix IPythonInterpreter unit test
[HOTFIX]: Fix IPythonInterpreter unit test

### What is this PR for?

This is for hotfix of `IPythonInterpreter` unit test failure. Just specify the version of ipython in `install_external_dependencies.sh`, otherwise latest ipython version will be installed, and the behavior may change.

### What type of PR is it?
[Hot Fix]

### Todos
* [ ] - Task

### What is the Jira issue?
*

### How should this be tested?
* CI pass

### Screenshots (if appropriate)

### Questions:
* Does the licenses files need update? No
* Is there breaking changes for older versions? No
* Does this needs documentation? No

Author: Jeff Zhang <zjffdu@apache.org>

Closes #2703 from zjffdu/ipython_version and squashes the following commits:

b4c7b42 [Jeff Zhang] HotFix: Fix IPythonInterpreter unit test

jongyoul/incubator-zeppelin,anthonycorbacho/incubator-zeppelin,tinkoff-dwh/zeppelin,pellmont/zeppelin,lresende/incubator-zeppelin,tzolov/incubator-zeppelin,sergeymazin/zeppelin,lresende/incubator-zeppelin,fogbeam/zeppelin_mirror,cquptEthan/incubator-zeppelin,hammertank/zeppelin,apache/zeppelin,joroKr21/incubator-zeppelin,cquptEthan/incubator-zeppelin,fogbeam/zeppelin_mirror,apache/zeppelin,vipul1409/zeppelin,datalayer/zeppelin,tzolov/incubator-zeppelin,hammertank/zeppelin,anthonycorbacho/incubator-zeppelin,jongyoul/incubator-zeppelin,yu74n/zeppelin,apache/incubator-zeppelin,sergeymazin/zeppelin,vipul1409/zeppelin,datalayer/zeppelin,joroKr21/incubator-zeppelin,lresende/incubator-zeppelin,datalayer/zeppelin,jongyoul/incubator-zeppelin,jongyoul/zeppelin,sergeymazin/zeppelin,yu74n/zeppelin,mwkang/zeppelin,zetaris/zeppelin,herval/zeppelin,jongyoul/zeppelin,jongyoul/incubator-zeppelin,Leemoonsoo/zeppelin,pellmont/zeppelin,jongyoul/zeppelin,karuppayya/zeppelin,prabhjyotsingh/incubator-zeppelin,joroKr21/incubator-zeppelin,VipinRathor/zeppelin,datalayer/zeppelin-datalayer,tinkoff-dwh/zeppelin,pellmont/zeppelin,VipinRathor/zeppelin,mwkang/zeppelin,lresende/incubator-zeppelin,apache/zeppelin,Leemoonsoo/zeppelin,r-kamath/zeppelin,vipul1409/zeppelin,r-kamath/zeppelin,VipinRathor/zeppelin,hammertank/zeppelin,jongyoul/zeppelin,r-kamath/zeppelin,anthonycorbacho/incubator-zeppelin,cquptEthan/incubator-zeppelin,r-kamath/zeppelin,tinkoff-dwh/zeppelin,joroKr21/incubator-zeppelin,prabhjyotsingh/zeppelin,pellmont/zeppelin,VipinRathor/zeppelin,r-kamath/incubator-zeppelin,r-kamath/incubator-zeppelin,karuppayya/zeppelin,prabhjyotsingh/zeppelin,datalayer/zeppelin-datalayer,apache/incubator-zeppelin,prabhjyotsingh/incubator-zeppelin,mwkang/zeppelin,zetaris/zeppelin,Leemoonsoo/incubator-zeppelin,r-kamath/incubator-zeppelin,apache/incubator-zeppelin,mwkang/zeppelin,Leemoonsoo/incubator-zeppelin,anthonycorbacho/incubator-zeppelin,zetaris/zeppelin,mwkang/zeppelin,hammertank/zeppelin,fogbeam/zeppelin_mirror,prabhjyotsingh/incubator-zeppelin,zjffdu/zeppelin,prabhjyotsingh/zeppelin,zjffdu/zeppelin,tinkoff-dwh/zeppelin,cquptEthan/incubator-zeppelin,prabhjyotsingh/incubator-zeppelin,Leemoonsoo/zeppelin,Leemoonsoo/incubator-zeppelin,apache/zeppelin,zjffdu/zeppelin,jongyoul/incubator-zeppelin,mwkang/zeppelin,Leemoonsoo/incubator-zeppelin,datalayer/zeppelin,tinkoff-dwh/zeppelin,anthonycorbacho/incubator-zeppelin,Leemoonsoo/zeppelin,prabhjyotsingh/incubator-zeppelin,datalayer/zeppelin,karuppayya/zeppelin,zjffdu/zeppelin,zetaris/zeppelin,sergeymazin/zeppelin,VipinRathor/zeppelin,cquptEthan/incubator-zeppelin,lresende/incubator-zeppelin,fogbeam/zeppelin_mirror,apache/zeppelin,anthonycorbacho/incubator-zeppelin,sergeymazin/zeppelin,joroKr21/incubator-zeppelin,apache/incubator-zeppelin,zetaris/zeppelin,tzolov/incubator-zeppelin,apache/incubator-zeppelin,prabhjyotsingh/incubator-zeppelin,datalayer/zeppelin-datalayer,prabhjyotsingh/zeppelin,datalayer/zeppelin-datalayer,zetaris/zeppelin,zetaris/zeppelin,vipul1409/zeppelin,zjffdu/zeppelin,tzolov/incubator-zeppelin,r-kamath/incubator-zeppelin,karuppayya/zeppelin,hammertank/zeppelin,r-kamath/zeppelin,zjffdu/zeppelin,sergeymazin/zeppelin,r-kamath/zeppelin,fogbeam/zeppelin_mirror,vipul1409/zeppelin,r-kamath/zeppelin,VipinRathor/zeppelin,herval/zeppelin,karuppayya/zeppelin,hammertank/zeppelin,herval/zeppelin,mwkang/zeppelin,Leemoonsoo/zeppelin,apache/incubator-zeppelin,cquptEthan/incubator-zeppelin,lresende/incubator-zeppelin,apache/zeppelin,joroKr21/incubator-zeppelin,fogbeam/zeppelin_mirror,Leemoonsoo/incubator-zeppelin,yu74n/zeppelin,jongyoul/zeppelin,hammertank/zeppelin,sergeymazin/zeppelin,yu74n/zeppelin,r-kamath/incubator-zeppelin,r-kamath/incubator-zeppelin,tinkoff-dwh/zeppelin,cquptEthan/incubator-zeppelin,yu74n/zeppelin,prabhjyotsingh/zeppelin,datalayer/zeppelin,karuppayya/zeppelin,vipul1409/zeppelin,prabhjyotsingh/zeppelin,r-kamath/incubator-zeppelin,joroKr21/incubator-zeppelin,herval/zeppelin,herval/zeppelin,yu74n/zeppelin,herval/zeppelin,prabhjyotsingh/zeppelin,Leemoonsoo/incubator-zeppelin,datalayer/zeppelin,pellmont/zeppelin,fogbeam/zeppelin_mirror,jongyoul/incubator-zeppelin,vipul1409/zeppelin,joroKr21/incubator-zeppelin,Leemoonsoo/zeppelin,pellmont/zeppelin,VipinRathor/zeppelin,herval/zeppelin,Leemoonsoo/zeppelin,tinkoff-dwh/zeppelin,apache/zeppelin,lresende/incubator-zeppelin,zjffdu/zeppelin,jongyoul/zeppelin,Leemoonsoo/zeppelin,tzolov/incubator-zeppelin,jongyoul/zeppelin,tzolov/incubator-zeppelin,yu74n/zeppelin,pellmont/zeppelin,anthonycorbacho/incubator-zeppelin,karuppayya/zeppelin