Revert "Stop extra framework copy during build ios-framework (#70790)" (#70802)

This reverts commit a9a35d10.

packages/flutter_tools/lib/src/commands/build_ios_framework.dart

@@ -453,6 +453,12 @@ end
       ' ├─Building plugins...'
     );
     try {
+      // Regardless of the last "flutter build" build mode,
+      // copy the corresponding engine.
+      // A plugin framework built with bitcode must link against the bitcode version
+      // of Flutter.framework (Release).
+      _project.ios.copyEngineArtifactToProject(mode);
+
       final String bitcodeGenerationMode = mode == BuildMode.release ?
           'bitcode' : 'marker'; // In release, force bitcode embedding without archiving.
 

packages/flutter_tools/lib/src/project.dart

@@ -648,11 +648,11 @@ class IosProject extends FlutterProjectPlatform implements XcodeBasedProject {
           ephemeralDirectory,
         );
       }
-      _copyEngineArtifactToModule(BuildMode.debug);
+      copyEngineArtifactToProject(BuildMode.debug);
     }
   }
 
-  void _copyEngineArtifactToModule(BuildMode mode) {
+  void copyEngineArtifactToProject(BuildMode mode) {
     // Copy podspec and framework from engine cache. The actual build mode
     // doesn't actually matter as it will be overwritten by xcode_backend.sh.
     // However, cocoapods will run before that script and requires something
@@ -662,9 +662,8 @@ class IosProject extends FlutterProjectPlatform implements XcodeBasedProject {
         Artifact.flutterFramework,
         platform: TargetPlatform.ios,
         mode: mode,
-      ));
-    final Directory engineCopyDirectory =
-        ephemeralDirectory.childDirectory('Flutter').childDirectory('engine');
+      )
+    );
     if (framework.existsSync()) {
       final File podspec = framework.parent.childFile('Flutter.podspec');
       globals.fsUtils.copyDirectorySync(
@@ -712,6 +711,12 @@ class IosProject extends FlutterProjectPlatform implements XcodeBasedProject {
     return registryDirectory.childFile('GeneratedPluginRegistrant.m');
   }
 
+  Directory get engineCopyDirectory {
+    return isModule
+        ? ephemeralDirectory.childDirectory('Flutter').childDirectory('engine')
+        : hostAppRoot.childDirectory('Flutter');
+  }
+
   Future<void> _overwriteFromTemplate(String path, Directory target) async {
     final Template template = await Template.fromName(
       path,