topic actions [nfc]: Check outbox message type first.
topic actions [nfc]: Check outbox message type first.

Outbox messages of type `private` will not have a comparable
`.display_recipient`, and will have no `.subject` at all.

While the comparisons currently performed are harmless and will, in
this case, yield the right result, it's cleaner conceptually (and
slightly safer when refactoring) to actually check the type first.

vishwesh3/zulip-mobile,vishwesh3/zulip-mobile,vishwesh3/zulip-mobile,vishwesh3/zulip-mobile