mc_issue_update() email missing latest notes

The mc_issue_update() could result in updating or adding notes to the issue.  Earlier in the method the issue and issue notes are loaded and cached.  Then notes are updated.  Then email API is called which loads the issue + notes again, but this time it hits stale cache.

Fixes #17763

api/soap/mc_issue_api.php

@@ -978,6 +978,10 @@ function mc_issue_update( $p_username, $p_password, $p_issue_id, $p_issue ) {
 				bugnote_add( $p_issue_id, $t_note['text'], mci_get_time_tracking_from_note( $p_issue_id, $t_note ), $t_view_state_id == VS_PRIVATE, $note_type, $note_attr, $t_user_id, FALSE );
 			}
 		}
+
+		# The issue has been cached earlier in the bug_get() call.  Flush the cache since it is
+		# now stale.  Otherwise, the email notification will be based on the cached data.
+		bugnote_clear_cache( $p_issue_id );
 	}
 
 	if ( isset ( $p_issue['tags']) && is_array ( $p_issue['tags']) ) {