i18n: wires up translations for plugins (#102853)

* i18n: consolidate i18n types & runtime services

* Chore: updates after PR feedback

* Chore: updates after feedback

* Chore: updates after feedback

* Chore: adds feature toggle

* Chore: adds locale to backend

* Chore: adds locales to i18n instance

* Chore: fix missing path in CODEOWNERS

* Chore: fix go lint issues

* Chore: fix missing path in CODEOWNERS

* Chore: updates after PR feedback

* Trigger build

* Chore: updates after PR feedback

* Chore: use resolved language for lookup

* Chore: updates after PR feedback

* Update pkg/plugins/plugins.go

Co-authored-by: Will Browne <wbrowne@users.noreply.github.com>

* Chore: updates after PR feedback

* Chore: updates after PR feedback

---------

Co-authored-by: Will Browne <wbrowne@users.noreply.github.com>

pkg/services/featuremgmt/toggles_gen.json

@@ -2469,6 +2469,18 @@
         "frontend": true
       }
     },
+    {
+      "metadata": {
+        "name": "localizationForPlugins",
+        "resourceVersion": "1742561476144",
+        "creationTimestamp": "2025-03-21T12:51:16Z"
+      },
+      "spec": {
+        "description": "Enables localization for plugins",
+        "stage": "experimental",
+        "codeowner": "@grafana/plugins-platform-backend"
+      }
+    },
     {
       "metadata": {
         "name": "logQLScope",