feat: add new actions to KeyringController (#6928)

## Explanation

Added actions for `createNewVaultAndKeychain` and
`createNewVaultAndRestore`. These are meant to be consumed by the
`createNewMultichainAccountWallet` method in the
`MultichainAccountService`.

## References

N/A

## 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 communicated my changes to consumers by [updating changelogs
for packages I've
changed](https://github.com/MetaMask/core/tree/main/docs/contributing.md#updating-changelogs),
highlighting breaking changes as necessary
- [x] I've prepared draft pull requests for clients and consumer
packages to resolve any breaking changes

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Adds messenger actions and handlers for `createNewVaultAndKeychain`
and `createNewVaultAndRestore`, and documents them in the changelog.
> 
> - **KeyringController**:
> - Add action types `KeyringControllerCreateNewVaultAndKeychainAction`
and `KeyringControllerCreateNewVaultAndRestoreAction` in
`src/KeyringController.ts`.
> - Extend `KeyringControllerActions` union to include the new actions.
> - Register action handlers for `${name}:createNewVaultAndKeychain` and
`${name}:createNewVaultAndRestore`.
> - **Docs**:
> - Update `packages/keyring-controller/CHANGELOG.md` under Unreleased
to note the new actions.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
e424f6b. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: hmalik88

packages/keyring-controller/CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add actions for `createNewVaultAndKeychain` and `createNewVaultAndRestore` ([#6928](https://github.com/MetaMask/core/pull/6928))
+  - These actions are meant to to be consumed by the `MultichainAccountService` in its `createMultichainAccountWallet` method.
+
 ### Changed
 
 - Bump `@metamask/base-controller` from `^8.4.1` to `^8.4.2` ([#6917](https://github.com/MetaMask/core/pull/6917))

packages/keyring-controller/src/KeyringController.ts

@@ -184,6 +184,16 @@ export type KeyringControllerWithKeyringAction = {
   handler: KeyringController['withKeyring'];
 };
 
+export type KeyringControllerCreateNewVaultAndKeychainAction = {
+  type: `${typeof name}:createNewVaultAndKeychain`;
+  handler: KeyringController['createNewVaultAndKeychain'];
+};
+
+export type KeyringControllerCreateNewVaultAndRestoreAction = {
+  type: `${typeof name}:createNewVaultAndRestore`;
+  handler: KeyringController['createNewVaultAndRestore'];
+};
+
 export type KeyringControllerAddNewKeyringAction = {
   type: `${typeof name}:addNewKeyring`;
   handler: KeyringController['addNewKeyring'];
@@ -226,7 +236,9 @@ export type KeyringControllerActions =
   | KeyringControllerSignUserOperationAction
   | KeyringControllerAddNewAccountAction
   | KeyringControllerWithKeyringAction
-  | KeyringControllerAddNewKeyringAction;
+  | KeyringControllerAddNewKeyringAction
+  | KeyringControllerCreateNewVaultAndKeychainAction
+  | KeyringControllerCreateNewVaultAndRestoreAction;
 
 export type KeyringControllerEvents =
   | KeyringControllerStateChangeEvent
@@ -1780,6 +1792,16 @@ export class KeyringController extends BaseController<
       `${name}:addNewKeyring`,
       this.addNewKeyring.bind(this),
     );
+
+    this.messagingSystem.registerActionHandler(
+      `${name}:createNewVaultAndKeychain`,
+      this.createNewVaultAndKeychain.bind(this),
+    );
+
+    this.messagingSystem.registerActionHandler(
+      `${name}:createNewVaultAndRestore`,
+      this.createNewVaultAndRestore.bind(this),
+    );
   }
 
   /**