fix: Lucee/Adobe UDFCasterException on getRouteCachingMetadata() null return

private struct function getRouteCachingMetadata() returned a bare `return;`
(null) for the common "route doesn't opt into caching" case. Lucee enforces
the declared struct return type strictly and throws
UDFCasterException: Cannot cast null value to value of type [struct]
on every request, which is why CI failed with 62 TestBox failures on
lucee@5/lucee@6 - any spec touching HandlerService (event execution,
handler bean lookups, etc) exercises getEventMetadataEntry(), which now
always calls this function.

Drop the explicit struct return type, matching the same
"function that may return null" convention RequestService.cfc's
getContextFromScope() already uses elsewhere in this codebase. Runtime
behavior is unchanged - callers already null-check with isNull().

Author: claude

system/web/services/HandlerService.cfc

@@ -825,7 +825,7 @@ component extends="coldbox.system.web.services.BaseService" accessors="true" {
 	 * @routeRecord    The current request's matched route record, i.e. `event.getCurrentRouteRecord()`. An empty struct when no route matched.
 	 * @requestContext The request context for the current request, passed to a closure `cacheSuffix` untouched.
 	 */
-	private struct function getRouteCachingMetadata( required struct routeRecord, required requestContext ){
+	private function getRouteCachingMetadata( required struct routeRecord, required requestContext ){
 		if ( !arguments.routeRecord.keyExists( "cache" ) || !arguments.routeRecord.cache ) {
 			return;
 		}