Make emoji selector text visible on dark mode, fixes #249

app/styles/emoji_picker.scss

@@ -109,6 +109,7 @@
   input {
     font-size: 14px;
     font-weight: 400;
+    color: var(--primary-text-color);
     padding: 7px 9px;
     font-family: inherit;
     display: block;