Don't push to selection history if selections are empty (#32433)
Michael Sloan
created
I got a panic during undo but haven't been able to repro it. Potentially
a consequence of my changes in #31731
> Thread "main" panicked with "There must be at least one selection" at
crates/editor/src/selections_collection.rs
Leaving release notes blank as I'm not sure this actually fixes the
panic
Release Notes:
- N/A