refactor(@angular/build): lazy load sourcemap remapping in i18n inliner worker

Previously, `@ampproject/remapping` was statically imported at the top level
of `i18n-inliner-worker.ts`, eagerly pulling in 5 packages
(`@ampproject/remapping` and 4 sub-dependencies) upon worker initialization.

In typical workflows or when sourcemaps are not requested for inlining,
remapping is never executed.

This changes the import of `@ampproject/remapping` to be dynamic so that
it is only loaded when a file actually requires sourcemap remapping.

Author: clydin

packages/angular/build/src/tools/i18n/i18n-inliner-worker.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import remapping, { type DecodedSourceMap, type SourceMapInput } from '@ampproject/remapping';
+import type { DecodedSourceMap, SourceMapInput } from '@ampproject/remapping';
 import type { ɵParsedTranslation } from '@angular/localize';
 import { MagicString } from 'magic-string';
 import { deserialize } from 'node:v8';
@@ -151,6 +151,8 @@ const deserializedTranslations = new Map<string, Promise<Record<string, ɵParsed
  */
 let currentGeneration: number | undefined;
 
+let remapping: typeof import('@ampproject/remapping').default | undefined;
+
 /**
  * Retrieves the file data for a filename, loading and extracting localization metadata.
  * If `cache` is true, the result is cached in `fileDataCache` across requests in this Worker.
@@ -542,6 +544,7 @@ async function inlineLocalize(
       includeContent: true,
       hires: 'boundary',
     });
+    remapping ??= (await import('@ampproject/remapping')).default;
     outputMap = remapping([{ ...rawMap, version: 3 } satisfies DecodedSourceMap, map], () => null);
   }