Add validation for rotation axis to SpringBoneSimulator3D

[TokageItLab]

• Follow up Implement SpringBoneSimulator3D to wiggle chained bones #101409.

The rotation axis locking is worked by snapping to a plane. Also, SpringBone obtains the next motion from the movement of the Vector3 coordinates by integrating and predicting. Then it cannot account for twisting due to the movement of child joints.

For example, if the forward and rotational axes are the same, the child joints may twist, but SpringBone's calculations cannot take account this force.

So, if the forward and rotation axes are the same unintended rotation will occur (although the corruption of Matrix is prevented), so this PR adds a validation to warn the user.

Also, added to the documentation that scaling is not recommended.

[fire]

This is a quality-of-life fix that avoids unintended rotation.

[fire]

This is a general thing, but how do we deal with things that may spam per frame, and the logging is worse than the bug?

[TokageItLab]

Since validation occurs only at the timing of value set, this should only cause spam if you ignore the warning and continue to change the value of the joint settings. In other words, the warning will not occur frame by frame unless you keep changing the joint settings.

However, if you have a chain of bones, warnings for all those joints may look like spam.

So when checking multiple axes at the same time, it might be bale to store a pair of setting and joints in a dictionary, so that we notify it in only one warning. However, I don't remember any other place in core that does that, so I don't know if I should do that.

At any rate, the possibility of spamming each frame does not occur in normal use, so I don't think there is any problem with merging as is.