Iterate on composition analysis reaction rotation

Why is this change being made?

As discussed in the Composition Analysis 16.6 retrospective, the team suggested improvements to the existing Reaction Rotation process.

The proposed changes address include:

1. Recognize that 15% of an engineer's time is not sufficient to perform all tasks.
2. Reduce the number of back-to-back rotations from 3 to potentially none.
3. Reduce the elapse period since a team member was last on rotation.
4. Align the rotation with the Cross-functional milestone planning.

The draft schedule for the new rotation is here: gitlab-org/secure&2.

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