Fix position the cursor at the end of the message when editing a message

[dylhack]

Description

Originally, pressing up to edit the latest event would bring your cursor to the start of the message.

Screen.Recording.2024-09-05.at.2.52.45.PM.mov

Fixes #1857

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

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]

All contributors have signed the CLA ✍️ ✅
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[dylhack]

I have read the CLA Document and I hereby sign the CLA

[github-actions]

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[ajbura]

LGTM. Thanks!