Add cmd2 monkeypatch for bug introduced in rich 15.0.0

[tleonhardt]

When rich fixed a bug in Text.from_ansi() that we reported, they introduced another bug. We should add a monkeypatch within cmd2 to work around this issue until rich fixes it on their end.

People have submitted PRs for this rich bug twice and the sole maintainer has immediately closed them. For one he explicitly said it was for violating AI policy but he didn't give a reason for the other one.

[kmvanbrunt]

I also posted a PR in the Rich repo.

Textualize/rich#4143