message_list_view: Remove check for mention class.
message_list_view: Remove check for mention class.

This check caused us to only run the code inside that block if the
message mentioned the current user (since that's when the `mention`
class is added to the main message row).

While this was a useful performance optimization, it probably was a
small one, not worth it for the correctness cost.

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