Upgrade ComposableController to extend BaseControllerV2 (#3590)

## Explanation

As part of the upcoming core wallet library initiative, we plan to
migrate all controllers to `BaseControllerV2`. This commit upgrades
`ComposableController`.

## References

- Closes #2082
- See #1509

## Changelog

### `@metamask/composable-controller`

## Added

- Add types `ComposableControllerState`,
`ComposableControllerStateChangeEvent`, `ComposableControllerEvents`,
`ComposableControllerMessenger`.

## Changed

- **BREAKING:** `ComposableController` is upgraded to extend
`BaseControllerV2`.
- The constructor now expects an options object with required properties
`controllers` and `messenger` as its only argument.
- `ComposableController` no longer has a `subscribe` method. Instead,
listeners for `ComposableController` events must be registered to the
controller messenger that generated the restricted messenger assigned to
the instance's `messagingSystem` class field.
- Any getters for `ComposableController` state that access the internal
class field directly should be refactored to instead use listeners that
are subscribed to `ComposableControllerStateChangeEvent`.

## Checklist

- [x] I've updated the test suite for new or updated code as appropriate
- [x] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [x] I've highlighted breaking changes using the "BREAKING" category
above as appropriate

---------

Co-authored-by: Ellilot Winkler <elliot.winkler@gmail.com>

packages/base-controller/src/BaseControllerV2.ts

@@ -113,13 +113,6 @@ export class BaseController<
 
   public readonly metadata: StateMetadata<ControllerState>;
 
-  /**
-   * The existence of the `subscribe` property is how the ComposableController detects whether a
-   * controller extends the old BaseController or the new one. We set it to `undefined` here to
-   * ensure the ComposableController never mistakes them for an older style controller.
-   */
-  public readonly subscribe: undefined;
-
   /**
    * Creates a BaseController instance.
    *

packages/composable-controller/CHANGELOG.md

@@ -5,6 +5,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Add types `ComposableControllerState`, `ComposableControllerStateChangeEvent`, `ComposableControllerEvents`, `ComposableControllerMessenger` ([#3590](https://github.com/MetaMask/core/pull/3590))
+
+### Changed
+- **BREAKING:** `ComposableController` is upgraded to extend `BaseControllerV2` ([#3590](https://github.com/MetaMask/core/pull/3590))
+  - The constructor now expects an options object with required properties `controllers` and `messenger` as its only argument.
+  - `ComposableController` no longer has a `subscribe` method. Instead, listeners for `ComposableController` events must be registered to the controller messenger that generated the restricted messenger assigned to the instance's `messagingSystem` class field.
+  - Any getters for `ComposableController` state that access the internal class field directly should be refactored to instead use listeners that are subscribed to `ComposableControllerStateChangeEvent`.
 
 ## [4.0.0]
 ### Changed