Dashboards: Cover the Switch variable in schema transformations - part 2. (#114549)

* feat: add v2alpha_1 conversion for the switch variable

* chore: gofmt fixes

* chore: update comments in tests

* chore: fix gofmt

* Update specs

* tests: update the v2alpha1 openapi snapshot

---------

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

apps/dashboard/pkg/migration/conversion/testdata/output/v1beta1.variable-conversions.v2beta1.json

@@ -318,6 +318,19 @@
           "description": "Group results by field"
         }
       },
+      {
+        "kind": "SwitchVariable",
+        "spec": {
+          "name": "switch_var",
+          "current": "false",
+          "enabledValue": "true",
+          "disabledValue": "false",
+          "label": "Enable Feature",
+          "hide": "dontHide",
+          "skipUrlSync": false,
+          "description": "Toggle feature on/off"
+        }
+      },
       {
         "kind": "QueryVariable",
         "spec": {