Update pipeline:run-full-rspec

What does this MR do and why?

Related to gitlab-org/quality/quality-engineering/team-tasks#1557 (closed)

This MR updates the label name from ~"pipeline:run-full-rspec" to pipeline:mr-approved to clarify its actual intent. I'm making this backward compatible so both labels will be supported until the roll out is fully complete and picked up by all branches in a few days.

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