chore: Modify gitignore to include generated ios/plist files (#12209)

## **Description**

Update gitignore so that we don't need to remember to stash ios
configuration after setup.

## **Related issues**

Fixes:

## **Manual testing steps**

1. Go to this page...
2.
3.

## **Screenshots/Recordings**

## **Pre-merge author checklist**

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Coding
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- [x] I've completed the PR template to the best of my ability
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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.

.gitignore

@@ -128,3 +128,6 @@ docs/assets/termsOfUse.html
 
 # build metadata
 android/app/src/main/assets/modules.json
+
+# Google firebase base64 derived configs
+**/GoogleService-Info.plist