refactor(tests): consolidate mock station creation utilities

refactor(tests): consolidate mock station creation utilities

Replaced 17 inline mock station objects in OCPPAuthServiceFactory.test.ts
with calls to createMockAuthServiceTestStation() from MockFactories.ts.

This reduces test file from 327 to 228 lines (~30% reduction) while
maintaining identical test behavior.

Remaining auth adapter tests retain inline mocks due to test-specific
method requirements (inAcceptedState, getLocalAuthListEnabled, etc.)
that are appropriately kept close to their test context.

All 280 tests pass.