Steps to reproduce:

1. Go to Page builder.
2. Add a block with a very long name, that exaggerates the length limit (255).
3. Publish the page.

Actual result: The platform throws an error (see the attachment).

Expected result: The error about the allowed signs limit is handled on the UI.

Discovered while testing: https://issues.ibexa.co/browse/IBX-7526

The fix needs to be re-tested on v4.6 Customizable Dashboard blocks as well.