deps: bump @vitest/coverage-istanbul from 4.1.1 to 4.1.2

Bumps [@vitest/coverage-istanbul](https://github.com/vitest-dev/vitest/tree/HEAD/packages/coverage-istanbul) from 4.1.1 to 4.1.2.
- [Release notes](https://github.com/vitest-dev/vitest/releases)
- [Commits](https://github.com/vitest-dev/vitest/commits/v4.1.2/packages/coverage-istanbul)

---
updated-dependencies:
- dependency-name: "@vitest/coverage-istanbul"
  dependency-version: 4.1.2
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -27,7 +27,7 @@
 	"devDependencies": {
 		"@cloudflare/vitest-pool-workers": "^0.13.4",
 		"@types/node": "^25.5.0",
-		"@vitest/coverage-istanbul": "4.1.1",
+		"@vitest/coverage-istanbul": "4.1.2",
 		"prettier": "^3.6.2",
 		"typescript": "^6.0.2",
 		"vite": "8.0.2",