…h ERC20 tokens (#1846)

Co-authored-by: Esteban Miño <efmino@uc.cl>

## **Description**

The primary currency toggle provides unnecessary overhead for every
asset feature we build. The Extension team is removing it for Extension
and we will do so as well for Mobile.
the default one on mobile will be Native.


## **Related issues**

Fixes:
[#1846](MetaMask/MetaMask-planning#1846 (comment))

## **Manual testing steps**

1. Go the setting page
2. Go to general
3. Primary currency toggle is removed, the default one is Native

## **Screenshots/Recordings**

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

### **Before**

<!-- [screenshots/recordings] -->
<img width="478" alt="Screenshot 2024-02-24 at 15 53 46"
src="https://github.com/MetaMask/metamask-mobile/assets/26223211/e45108fe-884a-4fcd-8fdb-3788e7448884">

### **After**

<!-- [screenshots/recordings] -->
<img width="499" alt="Screenshot 2024-02-24 at 15 42 12"
src="https://github.com/MetaMask/metamask-mobile/assets/26223211/adb343d1-114b-4bdf-b6c0-444f5832e62f">

## **Pre-merge author checklist**

- [x] I’ve followed [MetaMask Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've clearly explained what problem this PR is solving and how it
is solved.
- [x] I've linked related issues
- [x] I've included manual testing steps
- [x] I've included screenshots/recordings if applicable
- [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.
- [x] I’ve properly set the pull request status:
  - [ ] In case it's not yet "ready for review", I've set it to "draft".
- [x] In case it's "ready for review", I've changed it from "draft" to
"non-draft".

## **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.