Fix for UUM-148896

[sim-bz]

[Delete any line or section that does not apply]

Purpose of this PR

Changed static reset in CinemachineCore to happen during SubsystemRegistration

This could also be done with the AutoStaticCleanup attribute, but this is only available since 6000.5 and we'll need to backport this to the package version of Cinemachine.

Testing status

[Explanation of what’s tested, how tested and existing or new automation tests. Can include manual testing by self and/or QA. Specify test plans. Rarely acceptable to have no testing.]

• Added an automated test
• Passed all automated tests
• Manually tested

Documentation status

[Overview of how documentation is affected by this change. If there is no effect on documentation, explain why. Otherwise, state which sections are changed and why.]

• Updated CHANGELOG
• Updated README (if applicable)
• Commented all public classes, properties, and methods
• Updated user documentation

Technical risk

low halo, low complexity

Comments to reviewers

[Info per person for what to focus on, or historical info to understand who have previously reviewed and coverage. Help them get context.]

Package version

[Justification for updating either the patch, minor, or major version according to the semantic versioning rules]

• Updated package version

[u-pr]

💡 Harness Review

The runtime change is narrowly scoped, but one of the new regression tests does not actually verify the behavior it claims to cover.

_{Reviewed commit 17c6b85}

_{🤖 Helpful? 👍/👎}