Revert "chore: upgrade to flutter 3.0"

This reverts commit 3307e2f8fd.

frontend/app_flowy/lib/workspace/presentation/home/menu/app/section/section.dart

@@ -26,7 +26,7 @@ class ViewSection extends StatelessWidget {
         listenWhen: (p, c) => p.selectedView != c.selectedView,
         listener: (context, state) {
           if (state.selectedView != null) {
-            WidgetsBinding.instance.addPostFrameCallback((_) {
+            WidgetsBinding.instance?.addPostFrameCallback((_) {
               getIt<HomeStackManager>().setPlugin(state.selectedView!.plugin());
             });
           }

frontend/app_flowy/lib/workspace/presentation/plugins/doc/src/widget/toolbar/tool_bar.dart

@@ -184,7 +184,7 @@ class _ToolbarButtonListState extends State<ToolbarButtonList> with WidgetsBindi
     // Listening to the WidgetsBinding instance is necessary so that we can
     // hide the arrows when the window gets a new size and thus the toolbar
     // becomes scrollable/unscrollable.
-    WidgetsBinding.instance.addObserver(this);
+    WidgetsBinding.instance!.addObserver(this);
 
     // Workaround to allow the scroll controller attach to our ListView so that
     // we can detect if overflow arrows need to be shown on init.
@@ -226,7 +226,7 @@ class _ToolbarButtonListState extends State<ToolbarButtonList> with WidgetsBindi
   @override
   void dispose() {
     _controller.dispose();
-    WidgetsBinding.instance.removeObserver(this);
+    WidgetsBinding.instance!.removeObserver(this);
     super.dispose();
   }
 

frontend/app_flowy/lib/workspace/presentation/widgets/emoji_picker/src/emoji_picker.dart

@@ -135,7 +135,7 @@ class _EmojiPickerState extends State<EmojiPicker> {
     if (!loaded) {
       // Load emojis
       updateEmojiFuture.then(
-        (value) => WidgetsBinding.instance.addPostFrameCallback((_) {
+        (value) => WidgetsBinding.instance!.addPostFrameCallback((_) {
           if (!mounted) return;
           setState(() {
             loaded = true;

frontend/app_flowy/linux/flutter/generated_plugins.cmake

@@ -8,9 +8,6 @@ list(APPEND FLUTTER_PLUGIN_LIST
   window_size
 )
 
-list(APPEND FLUTTER_FFI_PLUGIN_LIST
-)
-
 set(PLUGIN_BUNDLED_LIBRARIES)
 
 foreach(plugin ${FLUTTER_PLUGIN_LIST})
@@ -19,8 +16,3 @@ foreach(plugin ${FLUTTER_PLUGIN_LIST})
   list(APPEND PLUGIN_BUNDLED_LIBRARIES $<TARGET_FILE:${plugin}_plugin>)
   list(APPEND PLUGIN_BUNDLED_LIBRARIES ${${plugin}_bundled_libraries})
 endforeach(plugin)
-
-foreach(ffi_plugin ${FLUTTER_FFI_PLUGIN_LIST})
-  add_subdirectory(flutter/ephemeral/.plugin_symlinks/${ffi_plugin}/linux plugins/${ffi_plugin})
-  list(APPEND PLUGIN_BUNDLED_LIBRARIES ${${ffi_plugin}_bundled_libraries})
-endforeach(ffi_plugin)

frontend/app_flowy/pubspec.lock

@@ -168,7 +168,7 @@ packages:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.16.0"
+    version: "1.15.0"
   connectivity_plus:
     dependency: "direct main"
     description:
@@ -357,7 +357,7 @@ packages:
       name: fake_async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0"
+    version: "1.2.0"
   ffi:
     dependency: transitive
     description:
@@ -645,7 +645,7 @@ packages:
       name: js
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.6.4"
+    version: "0.6.3"
   json_annotation:
     dependency: transitive
     description:
@@ -708,7 +708,7 @@ packages:
       name: material_color_utilities
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.4"
+    version: "0.1.3"
   meta:
     dependency: transitive
     description:
@@ -806,7 +806,7 @@ packages:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.1"
+    version: "1.8.0"
   path_drawing:
     dependency: transitive
     description:
@@ -1091,7 +1091,7 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.2"
+    version: "1.8.1"
   sprintf:
     dependency: transitive
     description:
@@ -1161,21 +1161,21 @@ packages:
       name: test
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.20.2"
+    version: "1.19.5"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.4.9"
+    version: "0.4.8"
   test_core:
     dependency: transitive
     description:
       name: test_core
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.4.11"
+    version: "0.4.9"
   textfield_tags:
     dependency: "direct main"
     description:
@@ -1294,7 +1294,7 @@ packages:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.2"
+    version: "2.1.1"
   video_player:
     dependency: transitive
     description:
@@ -1389,5 +1389,5 @@ packages:
     source: hosted
     version: "8.0.0"
 sdks:
-  dart: ">=2.17.0-0 <3.0.0"
+  dart: ">=2.15.0-116.0.dev <3.0.0"
   flutter: ">=2.5.0"