Fix TrackCache conflict when tracks have same name but different type

[TokageItLab]

Co-authored-by: Rémi Verschelde rverschelde@gmail.com

Using it could easily lead to use-after-free crashes, as the object may have been freed. Caching object pointers like this is unsafe. Instead, we rely only on the ObjectID and query ObjectDB with it each time we need access to the instance.

• Supersedes AnimationMixer: Remove Object pointer from TrackCache #85604
• Fixes Potential use-after-free in AnimationMixer due to dereferencing pointers to foreign objects, which may have been freed. #85365
• Fixes Animation Player crashes editor. #85572

This PR is a salvaged version of #49411 with more proper solution. Merge Value and Bezier track into the same cache. Also, make the hash generated from those track types and track paths the key of the cache map instead of the only track path.

However, as I mentioned in #49411 (comment), the Bezier and Value Tracks have different paths in most cases, and will not blend unless the paths are manually matched. So I believe it will be necessary to rework Bezier tracks to match path name with Value Tracks and manage subpath in a different way from current in the future.

• Fixes Bezier tracks can't fade in/out animations with AnimationTree #43848
• Fixes AnimationTree does not apply Call Method Track for a method in an AudioStreamPlayer script. #48526
• Fixes AnimationTree doesn't blend different track types #49431
• Fixes Animation Player fails to run script functions. #85571

[akien-mga]

Looks great!

Confirmed that it fixes the MRP in #85572.

[akien-mga]

Thanks!

[YuriSizov]

It breaks compatibility, so not suitable for cherry-picking.

[YuriSizov]

We discussed before how this could be done without breaking compat (basically, public API would remain the same, but internally we'd use ObjectIDs instead). So this could be submitted as a backport without breaking compat in this manner, if desired.