Dashboard Migrations: V34 CloudWatch Multi-Statistics Migration (#106656)

* wip: trying to understand how to get the ds info from migrator

* add datasource info provider

* Use DS service to fetch DS data

* add more tests cases to match with migrator cases

* Add snapshots

* Non-existing DS

* Add different DS for snapshots

* fix import

* Fix tests: guard against double initialization

* don't use full datasource package in test

* min version should be 35

* fix test

* fix conversion test

* Dashboards: Support schemaVersion v35 migration in backend

* Dashboards: Support schemaVersion v34 migration in backend

* Apply suggestions from code review

Co-authored-by: Stephanie Hingtgen <stephanie.hingtgen@grafana.com>

* Apply feedback

* Remove unused parameters

---------

Co-authored-by: Todd Treece <360020+toddtreece@users.noreply.github.com>
Co-authored-by: Haris Rozajac <haris.rozajac12@gmail.com>
Co-authored-by: Stephanie Hingtgen <stephanie.hingtgen@grafana.com>

apps/dashboard/pkg/migration/schemaversion/migrations.go

@@ -5,7 +5,7 @@ import (
 )
 
 const (
-	MIN_VERSION    = 34
+	MIN_VERSION    = 33
 	LATEST_VERSION = 41
 )
 
@@ -26,6 +26,7 @@ type DataSourceInfoProvider interface {
 
 func GetMigrations(dsInfoProvider DataSourceInfoProvider) map[int]SchemaVersionMigrationFunc {
 	return map[int]SchemaVersionMigrationFunc{
+		34: V34,
 		35: V35,
 		36: V36(dsInfoProvider),
 		37: V37,