fix(reactivity): fix WATCH_ARRAY v2 compat deep watching elements

close #11872

Author: thecodewarrior

packages/runtime-core/src/componentOptions.ts

@@ -860,22 +860,14 @@ export function createWatcher(
         ? currentInstance
         : null
 
-    const newValue = getter()
-    if (
-      isArray(newValue) &&
-      isCompatEnabled(DeprecationTypes.WATCH_ARRAY, instance)
-    ) {
-      options.deep = true
-    }
-
     const baseGetter = getter
     getter = () => {
       const val = baseGetter()
       if (
         isArray(val) &&
         checkCompatEnabled(DeprecationTypes.WATCH_ARRAY, instance)
       ) {
-        traverse(val)
+        traverse(val, 1)
       }
       return val
     }