Suppress console.warn noise in nonce-scrub spec

scrubScriptElements warns on every removed script, so three of
the four scrubScriptElements cases printed to stderr. Mocks and
restores console.warn around that describe block to keep test
output pristine, matching the convention already used in the
sibling describe block added for the same module's caller.

Author: myabc

frontend/src/turbo/csp-script-nonce.spec.ts

@@ -27,7 +27,7 @@
 //++
 
 import {
-  afterEach, describe, expect, it,
+  afterEach, beforeEach, describe, expect, it, vi,
 } from 'vitest';
 import { readScriptNonce, scrubScriptElements } from './csp-script-nonce';
 
@@ -48,6 +48,14 @@ describe('readScriptNonce', () => {
 });
 
 describe('scrubScriptElements', () => {
+  beforeEach(() => {
+    vi.spyOn(console, 'warn').mockImplementation(() => undefined);
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
   function scriptWithNonce(nonce:string | null):HTMLScriptElement {
     const script = document.createElement('script');
     if (nonce !== null) {