Add prompt before sending invalid commands

[cloudrac3r]

Description

This was previously a feature I added in #1435, but it got lost in a refactor. Here it is again.

When a message starts with / but didn't trigger a command, the popup will be shown. The popup allows sending it anyway, or going back to edit.

To make this work, I made the submit function async, which does not seem to have had any negative consequences.

This feature will prevent mistakes like this:

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

[github-actions]

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[ajbura]

as we now have wysiwyg editor command, emojis, mentions are only appear when they are picked explicitly or selected with the tab press, everything is suppose to work as appear into the editor. so it is not a good idea to add invalid command dialog because even when the command exist with specific prefixed plaintext it wont run unless it appear as cmd pill