message_viewport: Convert _.every used as loop to for…of.
message_viewport: Convert _.every used as loop to for…of.

Signed-off-by: Anders Kaseorg <dfdb7392591db597bc41cf266a9c3bc12a2706e5@zulipchat.com>

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