fix: Fix mistake in StatePropertyMetadataConstraint type

In the `next` export of `base-controller`, the type
`StatePropertyMetadataConstraint` mistakenly referenced the old metadata
property name `anonymous` rather than `includeInDebugSnapshot`. The type has
been updated to use the correct name.

Author: Gudahtt

packages/base-controller/CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- In experimental `next` export, fix the `StatePropertyMetadataConstraint` type ([#6942](https://github.com/MetaMask/core/pull/6942))
+  - It incorrectly used the old metadata property `anonymous` instead of `includeInDebugSnapshot`
+
 ## [8.4.2]
 
 ### Fixed

packages/base-controller/src/next/BaseController.ts

@@ -112,7 +112,7 @@ export type StateDeriverConstraint = (value: never) => Json;
  * This type can be assigned to any `StatePropertyMetadata` type.
  */
 export type StatePropertyMetadataConstraint = {
-  anonymous: boolean | StateDeriverConstraint;
+  includeInDebugSnapshot: boolean | StateDeriverConstraint;
   includeInStateLogs?: boolean | StateDeriverConstraint;
   persist: boolean | StateDeriverConstraint;
   usedInUi?: boolean;