floating_recipient_bar: Fix incorrect use of jQuery .next().
floating_recipient_bar: Fix incorrect use of jQuery .next().

The semantic of jQuery's .next(selector) return nothing if the
selector doesn't match the next child.

rht/zulip,kou/zulip,synicalsyntax/zulip,eeshangarg/zulip,punchagan/zulip,kou/zulip,brainwane/zulip,showell/zulip,synicalsyntax/zulip,kou/zulip,shubhamdhama/zulip,rht/zulip,timabbott/zulip,zulip/zulip,rishig/zulip,tommyip/zulip,brainwane/zulip,andersk/zulip,tommyip/zulip,synicalsyntax/zulip,timabbott/zulip,zulip/zulip,shubhamdhama/zulip,andersk/zulip,punchagan/zulip,shubhamdhama/zulip,kou/zulip,kou/zulip,brainwane/zulip,andersk/zulip,shubhamdhama/zulip,showell/zulip,zulip/zulip,showell/zulip,shubhamdhama/zulip,rht/zulip,shubhamdhama/zulip,zulip/zulip,hackerkid/zulip,brainwane/zulip,punchagan/zulip,andersk/zulip,rishig/zulip,tommyip/zulip,andersk/zulip,rishig/zulip,punchagan/zulip,synicalsyntax/zulip,eeshangarg/zulip,synicalsyntax/zulip,brainwane/zulip,brainwane/zulip,kou/zulip,andersk/zulip,showell/zulip,showell/zulip,synicalsyntax/zulip,eeshangarg/zulip,eeshangarg/zulip,kou/zulip,timabbott/zulip,tommyip/zulip,timabbott/zulip,rishig/zulip,hackerkid/zulip,showell/zulip,rishig/zulip,punchagan/zulip,shubhamdhama/zulip,hackerkid/zulip,zulip/zulip,showell/zulip,timabbott/zulip,rishig/zulip,tommyip/zulip,zulip/zulip,timabbott/zulip,timabbott/zulip,rht/zulip,hackerkid/zulip,punchagan/zulip,tommyip/zulip,andersk/zulip,tommyip/zulip,hackerkid/zulip,eeshangarg/zulip,rht/zulip,hackerkid/zulip,synicalsyntax/zulip,rht/zulip,rishig/zulip,brainwane/zulip,eeshangarg/zulip,punchagan/zulip,rht/zulip,hackerkid/zulip,eeshangarg/zulip,zulip/zulip