i18n: Garbage collect old translations from localStorage.
i18n: Garbage collect old translations from localStorage.

The old translation copies in localStorage were not being removed
when they were no longer needed, so we can free up the storage
by deleting them.

This was accidentally not merged months ago when originally
implemented, but it was written to fix #4443 and in fact does so.

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