## **Description**

The `SelectedNetworkController` state is cleared if any invalid
`networkConfigurationId`s are found in state. We are seeing reports of
this happening in production in v12.0.1.

The suspected cause is `NetworkController` state corruption. We resolved
a few cases of this in v12.0.1, but for users that were affected by
this, the invalid IDs may have propogated to the
`SelectedNetworkController` state already. That is what this migration
intends to fix.

[![Open in GitHub
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## **Related issues**

Fixes #26309

## **Manual testing steps**

We don't have clear reproduction steps for the bug itself. To
artificially reproduce the scenario by changing extension state, this
should work:

* Create a dev build from v12.0.2
* Install the dev build from the `dist/chrome` directory and proceed
through onboarding
* Visit the test dapp, refresh, and connect to it.
* Run this command in the background console:
  ```
  chrome.storage.local.get(
    null,
    (state) => {

state.data.SelectedNetworkController.domains['https://metamask.github.io']
= '123';
      chrome.storage.local.set(state, () => chrome.runtime.reload());
    }
  );
  ```
  * The linked error should now appear in the console of the popup
* Disable the extension
* Switch to this branch and create a dev build
* Enable and reload the extension
  * The error should no longer appear.

## **Screenshots/Recordings**

N/A

## **Pre-merge author checklist**

- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask
Extension Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [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-extension/blob/develop/.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.