fix(@angular/build): do not consider internal Angular files as external imports

When using the `application` build system with i18n enabled, the development
server may unintentionally attempt to optimize virtual internal files for
the locale data. These virtual files are now excluded from the list of
external imports.

Author: clydin

packages/angular/build/src/tools/esbuild/bundler-context.ts

@@ -366,6 +366,7 @@ export class BundlerContext {
         if (
           !external ||
           SERVER_GENERATED_EXTERNALS.has(path) ||
+          isInternalAngularFile(path) ||
           (kind !== 'import-statement' && kind !== 'dynamic-import' && kind !== 'require-call')
         ) {
           continue;