fix: add missing setPrincipalPermission mock in portability tests

The access service mock was missing the setPrincipalPermission function,
causing 5 test failures in the import flow.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

server/src/__tests__/company-portability.test.ts

@@ -18,6 +18,7 @@ const accessSvc = {
   ensureMembership: vi.fn(),
   listActiveUserMemberships: vi.fn(),
   copyActiveUserMemberships: vi.fn(),
+  setPrincipalPermission: vi.fn(),
 };
 
 const projectSvc = {