fix: Adding reactions in standup via mouse works more than once

[Dschoordsch]

Description

Fixes #10512
The popover would close before the emoji was selected. Switching its mode to modal fixes this issue.

Demo

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Testing scenarios

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[Dschoordsch]

There seems to be a bug in the controlling behaviour, removing onOpenChange instead would have the same effect and still properly open and close.

[Dschoordsch]

@mattkrick fyi, in case I missed something.