test(bundler-plugins): Increase timeout for webpack release-injection test (#26172)

**Why:** `injects the release only into initial chunks` runs a full
`mode: 'production'` webpack build within Vitest's default 5s timeout.
On cold Node 20 runners it often goes past that, and it caused 7 of the
10 recent `CI: Build & Test` failures on `develop` I looked at (details
in the issue). This gives it the same `{ timeout: 15_000 }` that the
sibling `child-compiler.test.ts` already uses. As agreed in the issue,
this is a first try; if it still flakes at 15s, the build itself needs a
look.

Locally the test passes in about 2.6–3.1s with the change (3 runs, Node
24).

Closes #26169

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: adityankale190895

packages/bundler-plugins/test/webpack/release-injection.test.ts

@@ -43,7 +43,7 @@ describe('release injection', () => {
     fs.rmSync(tmpDir, { recursive: true, force: true });
   });
 
-  it('injects the release only into initial chunks', async () => {
+  it('injects the release only into initial chunks', { timeout: 15_000 }, async () => {
     const outDir = path.join(tmpDir, 'dist');
 
     await build({