fix(duochat): Wait for another enter to send on IME

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fix(duochat): Wait for another enter to send on IME

When using IME such as japanese keyboard, users are given the opportunity to fix their typing before sending the message. That means formac this would require three enters (pick from list, confirm selection, and then send) and with Google keyboard IME it requires two (pick from list, and then send). So we wait for one additional enter to send the chat prompt

Normally, this is fixed using a form, but since we are adding more functionality from the slash commands this didn't seem to work on this context (example of fix using a form: gitlab!147814 (diffs))

Resolves #2537 (closed)

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Google Japanese IME

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MacOS IME

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