chore(deps-dev): bump vitest and @vitest/coverage-istanbul

Bumps [vitest](https://github.com/vitest-dev/vitest/tree/HEAD/packages/vitest) and [@vitest/coverage-istanbul](https://github.com/vitest-dev/vitest/tree/HEAD/packages/coverage-istanbul). These dependencies needed to be updated together.

Updates `vitest` from 2.1.5 to 2.1.8
- [Release notes](https://github.com/vitest-dev/vitest/releases)
- [Commits](https://github.com/vitest-dev/vitest/commits/v2.1.8/packages/vitest)

Updates `@vitest/coverage-istanbul` from 2.1.5 to 2.1.8
- [Release notes](https://github.com/vitest-dev/vitest/releases)
- [Commits](https://github.com/vitest-dev/vitest/commits/v2.1.8/packages/coverage-istanbul)

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

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -55,7 +55,7 @@
     "@types/node": "^22.10.3",
     "@typescript-eslint/eslint-plugin": "^8.12.2",
     "@typescript-eslint/parser": "^8.19.0",
-    "@vitest/coverage-istanbul": "^2.1.5",
+    "@vitest/coverage-istanbul": "^2.1.8",
     "eslint": "^8.57.1",
     "eslint-config-prettier": "^9.1.0",
     "eslint-plugin-node": "^11.1.0",
@@ -75,7 +75,7 @@
     "typescript": "^5.7.2",
     "unplugin-swc": "^1.5.1",
     "vite": "^5.4.11",
-    "vitest": "^2.1.4"
+    "vitest": "^2.1.8"
   },
   "optionalDependencies": {
     "@rollup/rollup-linux-x64-gnu": "^4.29.1",