upload: Fix send button selector in case of message-edit.
upload: Fix send button selector in case of message-edit.

Previously the selector returned an undefined element when trying to select
the message edit save button (since `closest` selects the closest parent in
the DOM tree). This is fixed in this commit.

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