fix(evals): add typecheck coverage for evals, integration-tests, and memory-tests (#25480)

integration-tests/hooks-system.test.ts

@@ -164,7 +164,8 @@ describe.skipIf(skipFlaky)(
         );
         expect(blockHook).toBeDefined();
         expect(
-          blockHook?.hookCall.stdout + blockHook?.hookCall.stderr,
+          (blockHook?.hookCall.stdout || '') +
+            (blockHook?.hookCall.stderr || ''),
         ).toContain(blockMsg);
       });