fix(docs-infra): remove duplicate event image asset entries

The v21 and v22 event images were listed as separate asset entries
(`src/assets/images/v21-event` and `src/assets/images/v22-event`) next to
`src/assets`, which already contains them. They were added when the
images were moved into their own Bazel packages, but the Bazel targets in
`APPLICATION_FILES` are what place the files under `src/assets`; the
extra entries only copy the same files to the same output location
(`assets/images/v2x-event/`) a second time.

The unit-test builder reuses these assets and copies them into the test
output. Since the first copy is read-only in the Bazel sandbox, the
duplicate copy fails with `EACCES: permission denied, copyfile`, which
breaks running `//adev:test` locally.

Remove the redundant entries. The production build output is unchanged
(all non-HTML files, including the event images, are byte-identical) and
`//adev:test` runs again without errors.

Author: MeAkib

adev/angular.json

@@ -26,14 +26,7 @@
             "polyfills": [],
             "tsConfig": "tsconfig.app.json",
             "inlineStyleLanguage": "scss",
-            "assets": [
-              "src/favicon.ico",
-              "src/robots.txt",
-              "src/llms.txt",
-              "src/assets",
-              "src/assets/images/v21-event",
-              "src/assets/images/v22-event"
-            ],
+            "assets": ["src/favicon.ico", "src/robots.txt", "src/llms.txt", "src/assets"],
             "styles": ["@angular/docs/styles/global-styles.scss", "./src/local-styles.scss"],
             "scripts": [],
             "webWorkerTsConfig": "tsconfig.worker.json",