chore: Adjust some colors

lib/pages/views/chat_view.dart

@@ -281,6 +281,12 @@ class ChatView extends StatelessWidget {
                                         : controller.canLoadMore
                                             ? Center(
                                                 child: OutlinedButton(
+                                                  style:
+                                                      OutlinedButton.styleFrom(
+                                                    backgroundColor: Theme.of(
+                                                            context)
+                                                        .scaffoldBackgroundColor,
+                                                  ),
                                                   onPressed:
                                                       controller.requestHistory,
                                                   child: Text(L10n.of(context)

lib/widgets/event_content/message_reactions.dart

@@ -101,7 +101,7 @@ class _Reaction extends StatelessWidget {
     final textColor = Theme.of(context).brightness == Brightness.dark
         ? Colors.white
         : Colors.black;
-    final color = Theme.of(context).secondaryHeaderColor;
+    final color = Theme.of(context).scaffoldBackgroundColor;
     final fontSize = DefaultTextStyle.of(context).style.fontSize;
     final padding = fontSize / 5;
     Widget content;

lib/widgets/event_content/state_message.dart

@@ -30,7 +30,7 @@ class StateMessage extends StatelessWidget {
             padding: const EdgeInsets.all(8),
             decoration: BoxDecoration(
               border: Border.all(
-                color: Theme.of(context).dividerColor,
+                color: Theme.of(context).secondaryHeaderColor,
               ),
               color: Theme.of(context).scaffoldBackgroundColor,
               borderRadius: BorderRadius.circular(AppConfig.borderRadius),