fix: Darktheme contrast fixes with primary color

lib/pages/chat/events/message.dart

@@ -391,8 +391,8 @@ class Message extends StatelessWidget {
               children: [
                 Container(
                   color: selected
-                      ? Theme.of(context).primaryColor.withAlpha(100)
-                      : Theme.of(context).primaryColor.withAlpha(0),
+                      ? Theme.of(context).colorScheme.primary.withAlpha(100)
+                      : Colors.transparent,
                   constraints: const BoxConstraints(
                     maxWidth: FluffyThemes.columnWidth * 2.5,
                   ),
@@ -410,7 +410,7 @@ class Message extends StatelessWidget {
                     child: Material(
                       color: Theme.of(context)
                           .colorScheme
-                          .background
+                          .surfaceVariant
                           .withOpacity(0.9),
                       elevation: Theme.of(context)
                               .appBarTheme

lib/pages/chat/events/message_reactions.dart

@@ -154,7 +154,7 @@ class _Reaction extends StatelessWidget {
           border: reacted!
               ? Border.all(
                   width: 1,
-                  color: Theme.of(context).primaryColor,
+                  color: Theme.of(context).colorScheme.primary,
                 )
               : null,
           borderRadius: BorderRadius.circular(AppConfig.borderRadius),

lib/pages/chat/reply_display.dart

@@ -64,7 +64,7 @@ class _EditContent extends StatelessWidget {
       children: <Widget>[
         Icon(
           Icons.edit,
-          color: Theme.of(context).primaryColor,
+          color: Theme.of(context).colorScheme.primary,
         ),
         Container(width: 15.0),
         FutureBuilder<String>(