Revert "Add service-nimbus android-component library metrics.yaml"

[badboy]

This reverts commit 12e0c63.

---

https://github.com/mozilla-mobile/firefox-android/blob/4fd5f8ff15ee73c11717ed465aa8f1519bc6df1b/android-components/components/service/nimbus/metrics.yaml contains nimbus_events.enrollment and others that are also defined in https://github.com/mozilla/application-services/blob/d58715194a98867372cdce8f75bd32b2e68b953b/components/nimbus/metrics.yaml#L12

We can't have the same definition twice and that's currently breaking probe-scraper (in turn leading to 500 errros on the push action).

[badboy]

Failing dry-run on main:

python3 -m probe_scraper.runner --dry-run --cache-dir tmp/cache --out-dir tmp/out --glean --glean-repo firefox-klar-android --glean-repo service-nimbus --glean-repo nimbus --glean-limit-date 2023-11-01

[badboy]

two bugs (https://bugzilla.mozilla.org/show_bug.cgi?id=1862764, https://bugzilla.mozilla.org/show_bug.cgi?id=1862765) had the metric-expiry-alert whiteboard tag which the test uses to search for filed bugs.
I removed the whiteboard tag and tests should be green again.