Summary:
In 1.18.10.27 Beta, the background of the open chat message is too large compared to 1.18.2.

Steps to Reproduce:

1. Go to Settings > Accessibility
2. Enable "Open Chat Message"
3. Open a world
4. Look at the background of the open chat message

Observed Results:
The background is too large.

Expected Results:
The background should be the same size as in 1.18.2.

Screenshots:
1.18.10.27 Beta:

1.18.2: