CI: Switch jest unit tests to self-hosted runners (#109304)

* trigger a workflow run for baseline

* attempt to improve caching with upfront action

* CYPRESS_INSTALL_BINARY: 0

* PUPPETEER_SKIP_DOWNLOAD: true

* use ubuntu-x64-large runners

* increase to 16 shards 🚀

* fix incorrect shard total

* ubuntu-x64 runners

* Revert "ubuntu-x64 runners"

This reverts commit 3411c7c5e1039263b17a3065cd7d45fa4c3c8f69.

* try caching node_modules

* fix flakey scopes test

* try just ubuntu-x64-large for yarn-install job

* run again, last one had a dodgy trace

* try different runners for yarn instlal

* Move node_modules cache steps to composite action, use ubuntu-x64 runners for everything

* fix duplicate runs-on

* specify shell for composite action

* fix some flaky tests

* update codeowners

* dedupe yarn.lock

* align yarn action, switch tests back to ubuntu-x64-large

* align yarn action cache keys

* fix required-frontend-unit-tests not checking repo out

* try without the node_modules magic

* actually skip the node_modules caching magic

* skip hardened mode

* skip downloading cypress

* comment

package.json

@@ -286,7 +286,7 @@
     "@grafana/llm": "0.22.1",
     "@grafana/monaco-logql": "^0.0.8",
     "@grafana/o11y-ds-frontend": "workspace:*",
-    "@grafana/plugin-ui": "0.10.8",
+    "@grafana/plugin-ui": "0.10.9",
     "@grafana/prometheus": "workspace:*",
     "@grafana/runtime": "workspace:*",
     "@grafana/scenes": "6.29.5",