…when removing dapp permitted chain (#15352)

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## **Description**

Having a chain permitted on a dapp, and then removing said network from
wallet throws an error when going back to dapp and trying to switch to
the currently selected network. Original ticket for the issue is
[here](#15201).

This PR makes sure we properly filter out the deleted network when
updating the permission for the currently selected network/s.

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## **Related issues**

Fixes:
#15201

## **Manual testing steps**

1. Go to any dapp via in app browser
2. Connect and permit a chain (ex.: Polygon)
3. Go back to wallet
4. Change selected chain (ex.: to Ethereum mainnet)
5. Remove the previously permitted chain from the available networks
(ex.: remove Polygon)
6. Go back to dapp and confirm adding the newly selected chain
7. No exception should show up ✅ 

## **Screenshots/Recordings**

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before and after of your change. -->

### **Before**


https://github.com/user-attachments/assets/a79b6b35-8690-4e3a-ba74-b8592e4300b8

### **After**


https://github.com/user-attachments/assets/001dd4c8-4c38-4464-91fb-a78058889feb

## **Pre-merge author checklist**

- [ ] 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).
- [ ] I've completed the PR template to the best of my ability
- [ ] I’ve included tests if applicable
- [ ] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] 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.