chore: Re-enable lint rules with no violations (#7267)

## Explanation

These lint rules were temporarily disabled at some point in the past,
but we still want to use them. There were no violations for any of these
rules, so they have been re-enabled.

Whatever violations motivated disabling these must have been
incidentally fixed since then.

Additionally, the modifications made for
`@typescript-eslint/switch-exhaustiveness-check` are now in the shared
config, so the override was no longer needed.

## References

N/A

## Checklist

- [x] I've updated the test suite for new or updated code as appropriate
- [x] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [x] I've communicated my changes to consumers by [updating changelogs
for packages I've
changed](https://github.com/MetaMask/core/tree/main/docs/contributing.md#updating-changelogs)
- [ ] I've introduced [breaking
changes](https://github.com/MetaMask/core/tree/main/docs/breaking-changes.md)
in this PR and have prepared draft pull requests for clients and
consumer packages to resolve them

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Removes several `off` overrides to re-enable ESLint rules and drops
the custom `@typescript-eslint/switch-exhaustiveness-check` config.
> 
> - **ESLint config (`eslint.config.mjs`)**:
> - Re-enable defaults by removing `off` overrides for:
`function-paren-newline`, `implicit-arrow-linebreak`,
`import-x/no-anonymous-default-export`, `lines-around-comment`,
`no-invalid-this`, `radix`.
> - Remove custom rule config for
`@typescript-eslint/switch-exhaustiveness-check`.
>   - All other rules/settings remain as before.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
25896e0. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: Gudahtt

eslint.config.mjs

@@ -31,20 +31,14 @@ const config = createConfig([
       'id-length': 'off',
 
       // TODO: re-enble most of these rules
-      'function-paren-newline': 'off',
       'id-denylist': 'off',
-      'implicit-arrow-linebreak': 'off',
-      'import-x/no-anonymous-default-export': 'off',
       'import-x/no-unassigned-import': 'off',
-      'lines-around-comment': 'off',
       'no-async-promise-executor': 'off',
       'no-case-declarations': 'off',
-      'no-invalid-this': 'off',
       'no-negated-condition': 'off',
       'no-new': 'off',
       'no-param-reassign': 'off',
       'no-restricted-syntax': 'off',
-      radix: 'off',
       'require-atomic-updates': 'off',
     },
     settings: {
@@ -115,14 +109,6 @@ const config = createConfig([
       },
     },
     rules: {
-      // These rules have been customized from their defaults.
-      '@typescript-eslint/switch-exhaustiveness-check': [
-        'error',
-        {
-          considerDefaultExhaustiveForUnions: true,
-        },
-      ],
-
       // TODO: Disable in `eslint-config-typescript`, tracked here: https://github.com/MetaMask/eslint-config/issues/413
       '@typescript-eslint/no-unnecessary-type-arguments': 'off',