api: Fix trailing '/' at end of jitsi server url.
api: Fix trailing '/' at end of jitsi server url.

Some users setup zulip with trailing / at end, like 'https://meet.jit.si/
leading to extra / on clients while generating video chat link.

This commit removes trailing '/' if it exists to make it consistent. Manual
testing was done by generating jitsi url.

Fixes #16225

kou/zulip,eeshangarg/zulip,rht/zulip,showell/zulip,andersk/zulip,punchagan/zulip,andersk/zulip,eeshangarg/zulip,zulip/zulip,showell/zulip,punchagan/zulip,zulip/zulip,andersk/zulip,eeshangarg/zulip,showell/zulip,eeshangarg/zulip,eeshangarg/zulip,zulip/zulip,andersk/zulip,hackerkid/zulip,zulip/zulip,rht/zulip,hackerkid/zulip,kou/zulip,zulip/zulip,hackerkid/zulip,eeshangarg/zulip,punchagan/zulip,rht/zulip,zulip/zulip,kou/zulip,hackerkid/zulip,hackerkid/zulip,rht/zulip,punchagan/zulip,rht/zulip,hackerkid/zulip,showell/zulip,andersk/zulip,hackerkid/zulip,kou/zulip,kou/zulip,punchagan/zulip,showell/zulip,punchagan/zulip,zulip/zulip,rht/zulip,kou/zulip,eeshangarg/zulip,andersk/zulip,showell/zulip,showell/zulip,rht/zulip,punchagan/zulip,andersk/zulip,kou/zulip