Update Angular to resolve vulnerability CVE-2021-4231

Versions of Angular < 11.0.5 have a cross-site scripting vulnerability as described at https://github.com/advisories/GHSA-c75v-2vq8-878f.

Start by locating the Angular dependency in the repository's dependency manifests and checking its current version against 11.0.5. Update it to a non-vulnerable version, then run the repository's existing checks; done means the dependency is no longer below 11.0.5 and the checks pass.

Written by the indexing model from the issue text.