feat: add removeAccount action (#7241)

## Explanation

Added an action for `removeAccount` in the keyring controller. Meant to
be used in the `MultichainAccountService` inside of a remove wallet
method.

## References

NA

## 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)
- [ ] I've introduced [breaking
changes](https://github.com/MetaMask/core/tree/main/docs/breaking-changes.md)
in this PR and have prepared draft pull requests for clients and
consumer packages to resolve them

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Exposes `removeAccount` via `KeyringController` messenger and
documents it in the changelog.
> 
> - **Keyring Controller**:
> - Add `KeyringControllerRemoveAccountAction` type and include it in
`KeyringControllerActions`.
> - Register `${name}:removeAccount` handler in
`#registerMessageHandlers` to invoke `removeAccount`.
> - **Docs**:
> - Update `packages/keyring-controller/CHANGELOG.md` under Unreleased
to mention the new `removeAccount` action.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
a3eccba. 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
+
+- Added an action to call `removeAccount` ([#7241](https://github.com/MetaMask/core/pull/7241))
+  - This action is meant to be consumed by the `MultichainAccountService` to encapsulate the act of removing a wallet when seed phrase backup fails in the clients.
+
 ## [25.0.0]
 
 ### Added

packages/keyring-controller/src/KeyringController.ts

@@ -199,6 +199,11 @@ export type KeyringControllerAddNewKeyringAction = {
   handler: KeyringController['addNewKeyring'];
 };
 
+export type KeyringControllerRemoveAccountAction = {
+  type: `${typeof name}:removeAccount`;
+  handler: KeyringController['removeAccount'];
+};
+
 export type KeyringControllerStateChangeEvent = {
   type: `${typeof name}:stateChange`;
   payload: [KeyringControllerState, Patch[]];
@@ -238,7 +243,8 @@ export type KeyringControllerActions =
   | KeyringControllerWithKeyringAction
   | KeyringControllerAddNewKeyringAction
   | KeyringControllerCreateNewVaultAndKeychainAction
-  | KeyringControllerCreateNewVaultAndRestoreAction;
+  | KeyringControllerCreateNewVaultAndRestoreAction
+  | KeyringControllerRemoveAccountAction;
 
 export type KeyringControllerEvents =
   | KeyringControllerStateChangeEvent
@@ -1817,6 +1823,11 @@ export class KeyringController<
       `${name}:createNewVaultAndRestore`,
       this.createNewVaultAndRestore.bind(this),
     );
+
+    this.messenger.registerActionHandler(
+      `${name}:removeAccount`,
+      this.removeAccount.bind(this),
+    );
   }
 
   /**