Fix organization deletion error messages (#107380)

* Fix organization deletion error messages

- Improve error message clarity when attempting to delete active organization
- Fix incorrect 'Failed to update organization' message to 'Failed to delete organization'
- Update comment to be more precise about the check being performed

Fixes #92792

* Improve error handling in organization deletion service

- Add contextual error message when dashboard deletion fails during org deletion
- Include organization ID in error message for better debugging
- Import fmt package for error formatting

This helps administrators understand which specific organization failed
during the deletion process when dashboard cleanup encounters issues.

* Fix typo in unified resource access error message

Change 'Namespace missmatch' to 'Namespace mismatch' for correct spelling.

pkg/services/org/orgimpl/org_delete_svc.go

@@ -3,6 +3,7 @@ package orgimpl
 import (
 	"context"
 	"errors"
+	"fmt"
 
 	"github.com/grafana/grafana/pkg/apimachinery/identity"
 	"github.com/grafana/grafana/pkg/infra/db"
@@ -59,7 +60,7 @@ func (s *DeletionService) Delete(ctx context.Context, cmd *org.DeleteOrgCommand)
 	ctx, _ = identity.WithServiceIdentity(ctx, cmd.ID)
 	err = s.dashSvc.DeleteAllDashboards(ctx, cmd.ID)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to delete dashboards for org %d: %w", cmd.ID, err)
 	}
 
 	return s.store.Delete(ctx, cmd)