Fix crypto mock in Cache.test.ts to preserve full module

The jest.mock('crypto') was replacing the entire module, causing
@smithy/uuid to fail with "Cannot read properties of undefined
(reading 'bind')" when @backstage/backend-test-utils was imported.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Fredrik Adelöw <freben@spotify.com>

packages/repo-tools/src/commands/package-docs/Cache.test.ts

@@ -24,11 +24,13 @@ import { readFile } from 'node:fs/promises';
 import { join as joinPath } from 'node:path';
 
 jest.mock('crypto', () => {
+  const actual = jest.requireActual('crypto');
   const hash = {
     update: jest.fn(),
     digest: jest.fn().mockReturnValue('test'),
   };
   return {
+    ...actual,
     createHash: jest.fn().mockReturnValue(hash),
   };
 });