Storage: Fix resource history sorting and pagination in Spanner backend (#102777)

* Align spanner ListHistory implementation with sql one

* Move migration logic

* Move migration code

---------

Co-authored-by: Marco de Abreu <18629099+marcoabreu@users.noreply.github.com>

pkg/storage/unified/resource/migrations.go

@@ -0,0 +1,30 @@
+package resource
+
+import (
+	"fmt"
+
+	"github.com/grafana/grafana/pkg/infra/log"
+)
+
+// MigrateVersionMatch handles backwards compatibility for ResourceVersionMatch
+// by migrating from the deprecated version_match to version_match_v2.
+// It returns an error if the version match is unknown.
+func MigrateListRequestVersionMatch(req *ListRequest, logger log.Logger) error {
+	if req.VersionMatch != nil && req.GetVersionMatchV2() == ResourceVersionMatchV2_UNKNOWN {
+		switch req.GetVersionMatch() {
+		case ResourceVersionMatch_DEPRECATED_NotOlderThan:
+			// This is not a typo. The old implementation actually did behave like Unset.
+			req.VersionMatchV2 = ResourceVersionMatchV2_Unset
+		case ResourceVersionMatch_DEPRECATED_Exact:
+			req.VersionMatchV2 = ResourceVersionMatchV2_Exact
+		default:
+			return fmt.Errorf("unknown version match: %v", req.GetVersionMatch())
+		}
+
+		// Log the migration to measure whether we have successfully migrated all clients
+		logger.Info("Old client request received, migrating from version_match to version_match_v2",
+			"oldValue", req.GetVersionMatch(),
+			"newValue", req.GetVersionMatchV2())
+	}
+	return nil
+}