Peertube theme: fix message action dropdown colors.

conversejs/custom/sass/_peertubetheme.scss

@@ -59,6 +59,20 @@
     background-color: var(--peertube-grey-background) !important;
   }
 
+  .message.chat-msg .chat-msg__actions {
+    // Fixing message actions colors
+    .dropdown-menu {
+      --text-color-lighten-15-percent: #8c8c8c; // default ConverseJS theme color
+
+      background-color: #fff; // this is the default bootstrap color, used by ConverseJS
+
+      i,
+      button {
+        color: #212529; // default bootstrap color for dropdown-items
+      }
+    }
+  }
+
   // hidding avatars when screen width is not big enough.
   @media screen and (max-width: 576px) {
     .message {