fix: Add name property to custom PermissionController errors

[Gudahtt]

Explanation

Add a name property to PermissionController custom errors.

This fixes a bug recently introduced in @metamask/multichain-api-middleware. A recent PR (#6985) assumed these name proeprties were already present.

References

Fixes error in #6985

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed, highlighting breaking changes as necessary
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes

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Note

Adds a base CustomError to set name on PermissionController errors, updates affected error classes and tests, and updates related changelogs (including multichain API middleware fix note).

• Permission Controller:
  • Errors: Introduce CustomError base that sets name; migrate multiple custom errors to extend it (e.g., InvalidSubjectIdentifierError, UnrecognizedSubjectError, Caveat* errors, etc.).
  • Tests: Add assertions for .name on CaveatMergeTypeMismatchError and EndowmentPermissionDoesNotExistError in src/errors.test.ts.
  • Docs: Update CHANGELOG.md with “Added” entry for error name property.
• Multichain API Middleware:
  • Docs: Update CHANGELOG.md with “Fixed” entry for wallet_revokeSession error handling referencing changes in @metamask/permission-controller.

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[Gudahtt]

We should revisit these tests at some point to cover all of the errors. I just added a test for the couple already tested for now.