fix(select): Fix NPE by checking for controller existence.
fix(select): Fix NPE by checking for controller existence.

In some cases, the select could be removed from the DOM before some
of the cleanup code was executed. This caused a `.controller()` call
to return `null`, but we did not check for existence before using
the controller which resulted in null pointer exception.

Fixes #7079.

Closes #7560

ErinCoughlan/material,robertmesserle/material,acoreyj/material,DerekLouie/material,ServiceManagementGroup/material,epelc/material,imjoeco/material,DevVersion/material,pwistbac/material,angular/material,Frank3K/material,hodeyp/material,acoreyj/material,programmist/material,vertazzar/material,welkinhealth/material,acoreyj/material,DevVersion/material,david-gang/material,j3ski/material,angular/material,DerekLouie/material,crisbeto/material,clshortfuse/material,Splaktar/material,gkalpak/material,imjoeco/material,dmitriz/material,marekmicek/material,gkalpak/material,pwistbac/material,bluebirdtech/material,jelbourn/material,epelc/material,SamDLT/material,graingert/material,hodeyp/material,crisbeto/material,hayloft/material,welkinhealth/material,HarrisCorp/material,colinskow/material,DerekLouie/material,jelbourn/material,miguelcobain/material,crisbeto/material,hodeyp/material,graingert/material,Splaktar/material,Frank3K/material,david-gang/material,vertazzar/material,oostmeijer/material,david-gang/material,daniel-nagy/material,ilovett/material,ErinCoughlan/material,crisbeto/material,miguelcobain/material,oostmeijer/material,programmist/material,jadjoubran/material,dmitriz/material,ServiceManagementGroup/material,gkalpak/material,welkinhealth/material,welkinhealth/material,SamDLT/material,miguelcobain/material,SamDLT/material,profoundry-us/material,robertmesserle/material,HipsterZipster/material,dmitriz/material,ErinCoughlan/material,imjoeco/material,HarrisCorp/material,graingert/material,clshortfuse/material,vertazzar/material,ilovett/material,jelbourn/material,j3ski/material,DevVersion/material,clshortfuse/material,bluebirdtech/material,gmoothart/material,bluebirdtech/material,pwistbac/material,hodeyp/material,DerekLouie/material,Splaktar/material,gkalpak/material,hayloft/material,clshortfuse/material,HarrisCorp/material,vertazzar/material,SamDLT/material,j3ski/material,oostmeijer/material,epelc/material,HipsterZipster/material,HipsterZipster/material,gmoothart/material,angular/material,ServiceManagementGroup/material,programmist/material,daniel-nagy/material,j3ski/material,daniel-nagy/material,graingert/material,Splaktar/material,robertmesserle/material,ServiceManagementGroup/material,daniel-nagy/material,jelbourn/material,colinskow/material,profoundry-us/material,jadjoubran/material,pwistbac/material,colinskow/material,ErinCoughlan/material,hayloft/material,marekmicek/material,gmoothart/material,marekmicek/material,jadjoubran/material,profoundry-us/material,jadjoubran/material,epelc/material,Frank3K/material,programmist/material,hayloft/material,ilovett/material,imjoeco/material,profoundry-us/material,robertmesserle/material,colinskow/material,DevVersion/material,Frank3K/material,oostmeijer/material,HarrisCorp/material,angular/material,miguelcobain/material,marekmicek/material,HipsterZipster/material,ilovett/material,acoreyj/material,david-gang/material,gmoothart/material,bluebirdtech/material,dmitriz/material