fix(@angular/build): exclude .angular from coverage in vitest

Similar to 3478aa3 but for vitest.

This avoids having to manually list `.angular` and all config files in `angular.json`

Author: cexbrayat

packages/angular/build/src/builders/unit-test/runners/vitest/executor.ts

@@ -9,6 +9,7 @@
 import type { BuilderOutput } from '@angular-devkit/architect';
 import assert from 'node:assert';
 import path from 'node:path';
+import { coverageConfigDefaults } from 'vitest/config';
 import type { InlineConfig, Vitest } from 'vitest/node';
 import { assertIsError } from '../../../../utils/error';
 import { loadEsmModule } from '../../../../utils/load-esm';
@@ -220,7 +221,17 @@ function generateCoverageOption(
     excludeAfterRemap: true,
     reportsDirectory: toPosixPath(path.join('coverage', projectName)),
     // Special handling for `exclude`/`reporters` due to an undefined value causing upstream failures
-    ...(codeCoverage.exclude ? { exclude: codeCoverage.exclude } : {}),
+    ...(codeCoverage.exclude
+      ? {
+          exclude: [
+            // Augment the default exclude https://vitest.dev/config/#coverage-exclude
+            // with the user defined exclusions and the CLI cache directory
+            '.angular/**',
+            ...codeCoverage.exclude,
+            ...coverageConfigDefaults.exclude,
+          ],
+        }
+      : {}),
     ...(codeCoverage.reporters
       ? ({ reporter: codeCoverage.reporters } satisfies VitestCoverageOption)
       : {}),