Remove BIP-44 flag and/or selector from confirmations code and keep State 2 code path only

### What is this about?

Remove the usage of the BIP-44 flag and/or selector (`isMultichainAccountsState2Enabled` and `selectMultichainAccountsState2Enabled`) from the confirmations area and simplify the code by keeping only the behavior that runs when the selector returns true (multichain accounts state 2 / BIP-44 path). This is a follow-up cleanup once the feature is considered stable and the legacy path is no longer needed.

- File: [app/components/Views/confirmations/hooks/send/useSendScope.ts](https://github.com/MetaMask/metamask-mobile/app/components/Views/confirmations/hooks/send/useSendScope.ts)
- File: [app/components/Views/confirmations/components/modals/switch-account-type-modal/account-network-row/account-network-row.tsx](https://github.com/MetaMask/metamask-mobile/app/components/Views/confirmations/components/modals/switch-account-type-modal/account-network-row.tsx)

### Scenario

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### Design

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### Technical Details

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### Threat Modeling Framework

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### Acceptance Criteria

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### Stakeholder review needed before the work gets merged

- [ ] Engineering (needed in most cases)
- [ ] Design
- [ ] Product
- [ ] QA (automation tests are required to pass before merging PRs but not all changes are covered by automation tests - please review if QA is needed beyond automation tests)
- [ ] Security
- [ ] Legal
- [ ] Marketing
- [ ] Management (please specify)
- [ ] Other (please specify)

### References

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Start by reading the two listed confirmation files: useSendScope.ts and account-network-row.tsx. Trace the isMultichainAccountsState2Enabled and selectMultichainAccountsState2Enabled usages, then verify that the confirmations area retains only the State 2 behavior and no longer depends on the legacy path.

Written by the indexing model from the issue text.