[MU4 Issue] [Assert] Crash on deleting characters in a Text

[HemantAntony]

Describe the bug When you delete the last character in a Text, MU crashes

To Reproduce Steps to reproduce the behavior:

1. Open a build with asserts enabled (like Debug)
2. Open a score
3. Add a Staff Text
4. Delete the characters in the Text
5. MU4 crashes on deleting the last character

Expected behavior MU4 should not crash

Screenshots Screencast from 20-12-22 06:37:32 PM IST.webm

Platform information

• OS: Ubuntu 22.04 LTS

Additional context

This happens only in Assert builds and not release builds