… and import of hd keyring (#14775)

<!--
Please submit this PR as a draft initially.
Do not mark it as "Ready for review" until the template has been
completely filled out, and PR status checks have passed at least once.
-->

## **Description**

This PR enables the discover Accounts call during import srp and
creation of a new vault.

Changes:
1. update `multiSrp/index` to call `addDiscoveredAccounts` and add
tests.
2. Updates `SolanaNewFeatureContent.test.tsx` to use the
`MultichainWalletSnapFactory`
3. Refactor name logic into a separate file `getMultichainAccountName`
in `AddNewAccount`
4. In `Authentication` `addDiscoveredAccounts` is called after
`createNewVaultandRestore` and `createNewVaultAndKeychain`

<!--
Write a short description of the changes included in this pull request,
also include relevant motivation and context. Have in mind the following
questions:
1. What is the reason for the change?
5. What is the improvement/solution?
-->

## **Related issues**

Fixes:

## **Manual testing steps**

Using the beta build.

Onboarding flow
1. With a new MM instance, create a new vault.
2. See that there is a new solana account along with the ethereum
account.

Import new srp during onboarding
1. With a new MM instance, import a new srp
2. See that there is a new solana account along with the ethereum
account.

With an existing MM vault.
1. Click on account selector.
2. Click on `Secrete Recovery Phrase`
3. Add a new srp.
4. See that there is a new solana account created after the import. 

## **Screenshots/Recordings**

<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

### **Before**

<!-- [screenshots/recordings] -->

### **After**

<!-- [screenshots/recordings] -->

## **Pre-merge author checklist**

- [x] I’ve followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I’ve included tests if applicable
- [x] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.