[NAVREDESIGN] TokensController support for all account

### **Description**

Update `TokensController` to support retrieving tokens for all accounts

### **Technical Details**

- Assuming the API that `TokensController` communicates with exposes an endpoint for fetching tokens 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=101%3A808
- ETA - 5 Days

Start by locating the TokensController and tracing the API request it makes for token retrieval. Verify whether the API exposes an endpoint for all accounts, then define and confirm the expected behavior for fetching one or more accounts; acceptance criteria are currently TBD.

Written by the indexing model from the issue text.