fix(evals): inconsistent imports in save_memory and hierarchical_memory evals

[Amartuvshins0404]

Problem

Two eval files import helpers from ../integration-tests/test-helper.js instead of the local ./test-helper.js:

• evals/save_memory.eval.ts (line 9-12) imports assertModelHasOutput and checkModelOutputContent from ../integration-tests/test-helper.js
• evals/hierarchical_memory.eval.ts (line 9) imports assertModelHasOutput from ../integration-tests/test-helper.js

Every other eval file imports these from ./test-helper.js, which re-exports them via export * from '@google/gemini-cli-test-utils'.

Why this matters

• Creates a fragile cross-directory dependency. If integration-tests/test-helper.js ever diverges or is refactored independently, these two evals would break for the wrong reason.
• Inconsistency makes the eval codebase harder for new contributors to follow. The convention is clearly to use the local ./test-helper.js.

Proposed fix

Update both files to import from ./test-helper.js instead:

// evals/save_memory.eval.ts
-import {
-  assertModelHasOutput,
-  checkModelOutputContent,
-} from '../integration-tests/test-helper.js';
+import {
+  assertModelHasOutput,
+  checkModelOutputContent,
+} from './test-helper.js';

// evals/hierarchical_memory.eval.ts
-import { assertModelHasOutput } from '../integration-tests/test-helper.js';
+import { assertModelHasOutput } from './test-helper.js';

Related to #23331