refactor(@angular/build): address PR #33715 review comments

- Replace unnecessary Promise.allSettled with direct dispose calls in execute-build.ts
- Rename SourceFileCache dispose() to override clear() and call super.clear() to clear base Map alongside internal cache structures

Author: alan-agius4

packages/angular/build/src/builders/application/execute-build.ts

@@ -167,7 +167,8 @@ export async function executeBuild(
     // without blocking the critical path of post-bundle optimization steps.
     // Any in-flight disposal is awaited in the builder action's finally block.
     if (!options.watch) {
-      void Promise.allSettled([angularCompilationContext?.dispose(), executionResult.dispose()]);
+      void angularCompilationContext?.dispose();
+      void executionResult.dispose();
     }
 
     // Return if the bundling has errors

packages/angular/build/src/tools/esbuild/angular/source-file-cache.ts

@@ -30,8 +30,8 @@ export class SourceFileCache extends Map<string, ts.SourceFile> {
    * rebuilds and can include the emitted contents of every TypeScript file in the
    * program. The cache is repopulated if a build is performed after this is called.
    */
-  dispose(): void {
-    this.clear();
+  override clear(): void {
+    super.clear();
     this.modifiedFiles.clear();
     this.typeScriptFileCache.clear();
     this.loadResultCache.clear();

packages/angular/build/src/tools/esbuild/bundler-execution-result.ts

@@ -208,7 +208,7 @@ export class ExecutionResult {
         this.componentStyleBundler.dispose(),
       ]);
     } finally {
-      this.codeBundleCache?.dispose();
+      this.codeBundleCache?.clear();
     }
   }
 }