feat(accounts-controller): add account.options.groupIndex for native EVM accounts (#6122)

## Explanation

We need this information to be able to group EVM accounts under their
proper multichain accounts.

## References

N/A

## Changelog

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
- [ ] I've prepared draft pull requests for clients and consumer
packages to resolve any breaking changes

Author: ccharly

packages/accounts-controller/CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add `groupIndex` to EVM HD account options ([#6122](https://github.com/MetaMask/core/pull/6122))
+
 ### Changed
 
 - **BREAKING:** Bump peer dependency `@metamask/snaps-controllers` from `^12.0.0` to `^14.0.0` ([#6035](https://github.com/MetaMask/core/pull/6035))

packages/accounts-controller/src/AccountsController.ts

@@ -706,6 +706,8 @@ export class AccountsController extends BaseController<
             // getting the keyring instance here feels a bit overkill.
             // This will be naturally fixed once every keyring start using `KeyringAccount` and implement the keyring API.
             derivationPath: getDerivationPathForIndex(accountIndex),
+            // Required now for multichain accounts.
+            groupIndex: accountIndex,
           };
         }
 

packages/accounts-controller/src/tests/mocks.ts

@@ -111,11 +111,12 @@ export const createMockInternalAccountOptions = (
   keyringIndex: number,
   keyringType: KeyringTypes,
   groupIndex: number,
-): Record<string, string> => {
+): Record<string, string | number> => {
   if (keyringType === KeyringTypes.hd) {
     return {
       entropySource: `mock-keyring-id-${keyringIndex}`,
       derivationPath: `m/44'/60'/0'/0/${groupIndex}`,
+      groupIndex,
     };
   }