[NAVREDESIGN] TransactionsController support for all accounts

### **Description**

Update `TransactionsController` to support retrieving transactions for all accounts

### **Technical Details**

- Assuming the API that `TransactionsController` communicates with exposes an endpoint for fetching transactions for all accounts, we'll just need to update the controller to allow for fetching one or more accounts.

### **Acceptance Criteria**

- TBD

### **References**

- Figma - https://www.figma.com/file/qcwJHEEw5qyNru5mbFf6Oq/Nav-Redesign-Breakdown?node-id=102%3A258
- ETA - 5 Days

Locate TransactionsController and inspect the API endpoint it currently uses, then review the linked Figma navigation redesign. Confirm whether the API supports fetching transactions for one or more accounts; done means the controller retrieves transactions for all requested accounts, with acceptance criteria still needing definition.

Written by the indexing model from the issue text.