drafts.js: Prevent delete from triggering in the back of draft overlay.
drafts.js: Prevent delete from triggering in the back of draft overlay.

Fixes #4340.

mahim97/zulip,SmartPeople/zulip,kou/zulip,eeshangarg/zulip,tommyip/zulip,Galexrt/zulip,SmartPeople/zulip,punchagan/zulip,kou/zulip,ryanbackman/zulip,ryanbackman/zulip,amanharitsh123/zulip,verma-varsha/zulip,dhcrzf/zulip,timabbott/zulip,hackerkid/zulip,tommyip/zulip,punchagan/zulip,timabbott/zulip,christi3k/zulip,jrowan/zulip,brockwhittaker/zulip,brainwane/zulip,brainwane/zulip,Galexrt/zulip,j831/zulip,amanharitsh123/zulip,zulip/zulip,rht/zulip,zulip/zulip,mahim97/zulip,dhcrzf/zulip,christi3k/zulip,vaidap/zulip,dhcrzf/zulip,vaidap/zulip,andersk/zulip,verma-varsha/zulip,jackrzhang/zulip,verma-varsha/zulip,showell/zulip,jrowan/zulip,rht/zulip,eeshangarg/zulip,verma-varsha/zulip,jphilipsen05/zulip,verma-varsha/zulip,showell/zulip,punchagan/zulip,brockwhittaker/zulip,showell/zulip,showell/zulip,jrowan/zulip,eeshangarg/zulip,ryanbackman/zulip,christi3k/zulip,andersk/zulip,timabbott/zulip,jackrzhang/zulip,showell/zulip,kou/zulip,ryanbackman/zulip,andersk/zulip,rishig/zulip,zulip/zulip,hackerkid/zulip,amanharitsh123/zulip,vaidap/zulip,vabs22/zulip,eeshangarg/zulip,rishig/zulip,hackerkid/zulip,dhcrzf/zulip,eeshangarg/zulip,eeshangarg/zulip,brainwane/zulip,timabbott/zulip,christi3k/zulip,synicalsyntax/zulip,kou/zulip,shubhamdhama/zulip,hackerkid/zulip,rht/zulip,rishig/zulip,shubhamdhama/zulip,rishig/zulip,christi3k/zulip,brainwane/zulip,brockwhittaker/zulip,tommyip/zulip,Galexrt/zulip,jrowan/zulip,verma-varsha/zulip,j831/zulip,punchagan/zulip,jackrzhang/zulip,punchagan/zulip,rishig/zulip,j831/zulip,jackrzhang/zulip,jackrzhang/zulip,j831/zulip,zulip/zulip,shubhamdhama/zulip,vabs22/zulip,vaidap/zulip,mahim97/zulip,tommyip/zulip,brainwane/zulip,andersk/zulip,showell/zulip,eeshangarg/zulip,punchagan/zulip,timabbott/zulip,kou/zulip,jphilipsen05/zulip,vabs22/zulip,jphilipsen05/zulip,SmartPeople/zulip,zulip/zulip,jrowan/zulip,amanharitsh123/zulip,mahim97/zulip,tommyip/zulip,vabs22/zulip,jackrzhang/zulip,jackrzhang/zulip,punchagan/zulip,SmartPeople/zulip,brainwane/zulip,dhcrzf/zulip,brockwhittaker/zulip,tommyip/zulip,amanharitsh123/zulip,rht/zulip,Galexrt/zulip,timabbott/zulip,synicalsyntax/zulip,christi3k/zulip,synicalsyntax/zulip,vabs22/zulip,jphilipsen05/zulip,dhcrzf/zulip,kou/zulip,rishig/zulip,kou/zulip,vaidap/zulip,j831/zulip,synicalsyntax/zulip,rht/zulip,SmartPeople/zulip,mahim97/zulip,ryanbackman/zulip,hackerkid/zulip,Galexrt/zulip,Galexrt/zulip,amanharitsh123/zulip,showell/zulip,dhcrzf/zulip,shubhamdhama/zulip,synicalsyntax/zulip,jphilipsen05/zulip,rht/zulip,zulip/zulip,tommyip/zulip,jrowan/zulip,brockwhittaker/zulip,Galexrt/zulip,j831/zulip,shubhamdhama/zulip,vaidap/zulip,shubhamdhama/zulip,hackerkid/zulip,brockwhittaker/zulip,rishig/zulip,timabbott/zulip,ryanbackman/zulip,rht/zulip,brainwane/zulip,mahim97/zulip,zulip/zulip,andersk/zulip,hackerkid/zulip,andersk/zulip,andersk/zulip,SmartPeople/zulip,vabs22/zulip,synicalsyntax/zulip,shubhamdhama/zulip,synicalsyntax/zulip,jphilipsen05/zulip