It's time (maybe somewhat late) to remove some deprecated stuff for the
runner.
- `x-runner-version`: runners needn't to report version in every
request, they will call `Declare`.
- `AgentLabels`: runners will report them as `Labels`.
(cherry picked from commit b9396a9b852e4fea0e2c39ef3ef2fdfbc9ea248a)
Conflicts:
routers/api/actions/runner/interceptor.go
trivial conflict because
e80466f734 Resolve lint for unused parameter and unnecessary type arguments (#30750)
was not cherry-picked
38ea77ebbe