feat(@angular/build): add quiet option to suppress build noise in unit tests

The unit-test builder currently triggers a rebuild of the application on each test run in watch mode. This causes the application builder to print a full list of built files on every rebuild, which can be quite noisy and not useful during test development.

This change introduces a `quiet` option to the `@angular/build:unit-test` builder. When enabled, it suppresses the build summary and stats table from the application builder. The option defaults to `true` when running locally to provide a cleaner development experience, and defaults to `false` when running in a CI environment to ensure detailed logs are available for troubleshooting.