messsage_view_header: Remove flex set via :not().
messsage_view_header: Remove flex set via :not().

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