[occm] Fix serviceMonitor labelSelector and remove deprecated bearerTokenFile auth - #3039

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744, actions/setup-python@7f4fc3e22c37d6ff65e88745f38bd3157c663f7c, azure/setup-helm@5119fcb9089d432beecbf79bb2c7915207344b78. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/