fix(ivy): ngcc - write .d.ts.map files to the correct folder (#29556)

Previously we were writing `.d.ts` and `.d.ts.map` to different
folders.

PR Close #29556

packages/compiler-cli/ngcc/src/writing/new_entry_point_file_writer.ts

@@ -52,7 +52,8 @@ export class NewEntryPointFileWriter extends InPlaceFileWriter {
 
   protected writeFile(file: FileInfo, entryPointPath: AbsoluteFsPath, newDir: AbsoluteFsPath):
       void {
-    if (isDtsPath(file.path)) {
+    if (isDtsPath(file.path.replace(/\.map$/, ''))) {
+      // This is either `.d.ts` or `.d.ts.map` file
       super.writeFileAndBackup(file);
     } else {
       const relativePath = relative(entryPointPath, file.path);