{AKS} Mark update app monitoring test as live_only

Back-to-back AKS update tests are inherently incompatible with VCR
cassette recording — the CI runs against real Azure without setting
AZURE_TEST_RUN_LIVE, causing VCR to replay stale cassette responses
that don't match the actual cluster state.

Mark the test @live_only() to match the pattern used by the analogous
metrics enable/disable test, and simplify the wait to use self.cmd()
directly since VCR is no longer involved. Delete the recording file.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: tokaplan