V2 Schema + DD: Patch fast with dashboard fixes related to V2 Schema and dynamic dashboards. (#115620)

* V2: Fix ad hoc filter defaultKeys incorrectly set to static mode (#115508)

* V2: Fix ad hoc filter defaultKeys incorrectly set to static mode

* Fixture update

* Dashboard Schema v1beta1 to v2alpha1: Preserve string template variable datasource references in query variables (#115516)

* Dashboard migration: preserve legacy string datasource references

Fix v1beta1 → v2alpha1 conversion to handle legacy string datasource
references in QueryVariable, AdhocVariable, and GroupByVariable.

Previously, string datasource references (both template variables like
"$datasource" and direct names/UIDs like "prometheus") were being
dropped during conversion, causing variable chaining to break.

The frontend's DatasourceSrv.getInstanceSettings() already handles
string references by trying uid → name → id lookup at runtime, so we
preserve the string in the uid field and let the frontend resolve it.

* trigger frontend ci tests when dashboard migration code changes

* v1: if string convert to DS ref

* Update migration testdata to fix template variable datasource references

* update

* Schema V2: Always set unique refid for queries in conversion V1 -> V2 (#115534)

Always set unique refid in conversion

* Dashboards: Fix text panel content loss during v1 to v2 migration (#115496)

* move content and mode properties to options level

* move to angular section

* Update comments

* handle missing angular text panel

* re-generate test files

* angualr panels tests

* fixing test

* Update output files

* Update output for dev dashboard

* Spread options at the top panel level for migration

* linting issue

---------

Co-authored-by: Ivan Ortega <ivanortegaalba@gmail.com>

* V2 -> V1 conversion: include empty properties array when converting overrides (#115495)

* adjust conversion file to include empty properties array in overrides

* fix lint error

* add test case for empty properties and fix incorrect regex to v1 conversion

* Dashboard: change export dropdown placement in sidebar (#115515)

Update export menu placement

---------

Co-authored-by: Dominik Prokop <dominik.prokop@grafana.com>
Co-authored-by: Haris Rozajac <58232930+harisrozajac@users.noreply.github.com>
Co-authored-by: Kristina Demeshchik <kristina.demeshchik@gmail.com>
Co-authored-by: Ivan Ortega <ivanortegaalba@gmail.com>
Co-authored-by: Sergej-Vlasov <37613182+Sergej-Vlasov@users.noreply.github.com>

apps/dashboard/pkg/migration/testdata/input/v15.mimir_rollout_debugging.json

@@ -654,7 +654,9 @@
           "text": "prod",
           "value": "prod"
         },
-        "datasource": "$datasource",
+        "datasource": {
+          "uid": "$datasource"
+        },
         "hide": 0,
         "includeAll": true,
         "label": "cluster",
@@ -677,7 +679,9 @@
           "text": "prod",
           "value": "prod"
         },
-        "datasource": "$datasource",
+        "datasource": {
+          "uid": "$datasource"
+        },
         "hide": 0,
         "includeAll": false,
         "label": "namespace",