bug: telemetry custom messages box clipping

[ES-Alexander]

Bug description

Steps to reproduce

1. Go to Settings / Telemetry
2. Expand the Custom Messages section
3. Click to create a new custom message
4. The text entry is clipped on the right

Primary pain point(s)

Looks unpleasant, and it's unclear whether there are missing UI elements missing that are hidden because of it (e.g. some kind of confirmation button).

Additional context

No response

Prerequisites

• I have checked to make sure that a similar request has not already been filed or fixed.