A few bugfixes:

A few bugfixes:

* #19583: Keying Sets list issues
Deleting a Keying Set (or a Keying Set Path) set the active index to 0, but that would mean that the first item would be selected but not visible.

* #19590: Keyframing properties of a modifier with more than one of it's type the property will highlight in all
- Modifiers now always have a unique name, so renaming a modifier should check that the name is unique. Most of the files changed in this commit were just to make sure that modifiers got unique names when they were created
- Modifiers path getter was wrapped a bit wrong (missing the "s around the name)

* Constraints Bugs
- Constraints renaming now also makes sure the names stay unique
- Fixed (or attempted to fix) compiler warnings about some enum declaration for distance constraint