test(react): add tests and mocks for invitation components

[rax7389]

Changes

Summary: Adds comprehensive test coverage and reusable mock utilities for all invitation management components and hooks introduced in earlier PRs.

Why: This PR adds the full test suite, ensuring every component and hook is covered for rendering, user interactions, edge cases, and accessibility. Reusable mock factories are provided so future tests can spin up test data consistently.

What:

Test Suites

1. InvitationDetailsModal tests — Rendering, role resolution, read-only mode, button states.

2. InvitationRevokeModal tests — Revoke vs revoke-and-resend flows, confirmation callbacks.

3. InvitationTableActionsColumn tests — Context-aware actions, Copy URL visibility, read-only mode.

4. InvitationCreateModal tests — Zod validation, duplicate email rejection, form submission.

5. SearchFilter tests — Role filter rendering, empty roles handling.

describe('SearchFilter', () => {
  it('should render role filter with available roles', () => { ... });
  it('should return null when no roles available', () => { ... });
});

6. useMemberManagementService tests — Service layer hook tests for API calls and mutations.

Mock Utilities

invitation.mocks.ts — Reusable factory functions for consistent test data:

createMockInvitation(overrides?)        // Base invitation with sensible defaults
createMockPendingInvitation(overrides?) // Invitation with future expires_at
createMockExpiredInvitation(overrides?) // Invitation with past expires_at
createMockRoles()                       // [Admin, Member, Viewer]
createMockProviders()                   // [Google, GitHub]
createMockSearchFilterProps(overrides?) // Full props for SearchFilter

core-client.mocks.ts — Added invitations mock methods (list, get, create, delete) to createMockMyOrgApiService.

References

Part of the member management invitations feature.

Testing

• This change adds unit test coverage
• This change has been tested on the latest version of the platform/language

All tests pass. Run with npm run test from packages/react.

Checklist

• I have read the Auth0 general contribution guidelines
• I have read the Auth0 Code of Conduct
• All existing and new tests complete without errors