fix(runtime-core): improve dedupe listeners when attr fallthrough (#4912)

fix #4859

packages/runtime-core/src/vnode.ts

@@ -791,7 +791,10 @@ export function mergeProps(...args: (Data & VNodeProps)[]) {
       } else if (isOn(key)) {
         const existing = ret[key]
         const incoming = toMerge[key]
-        if (existing !== incoming) {
+        if (
+          existing !== incoming &&
+          !(isArray(existing) && existing.includes(incoming))
+        ) {
           ret[key] = existing
             ? [].concat(existing as any, incoming as any)
             : incoming