Cloudwatch: Fix LaunchTime attribute tag bug (#20237)

* Cast tags of type Time to string

* Fig go lint issue

(cherry picked from commit 359416b89f)

pkg/tsdb/cloudwatch/metric_find_query.go

@@ -550,6 +550,8 @@ func (e *CloudWatchExecutor) handleGetEc2InstanceAttribute(ctx context.Context,
 				}
 				if attr, ok := v.Interface().(*string); ok {
 					data = *attr
+				} else if attr, ok := v.Interface().(*time.Time); ok {
+					data = (*attr).String()
 				} else {
 					return nil, errors.New("invalid attribute path")
 				}