Chat messages sent by uid are not shown in chat windows opened by the same uid

[julianlam]

Repro Steps

If "A" has two browser windows open, and "B" sends a message to A, two chat windows open for "A", one on each browser.

If "A" then sends a message to "B", the other browser window does not show that message sent.

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Easiest solution may be to simplify the logic:

• Remove client-side update of chat window on message send
• Remove "did I sent this message? if so, do nothing" logic on client, if it even exists
• Add behaviour to disable text input while waiting for socket return, to prevent spamming (maybe add a loader icon as well)