Remove progress bar, loading chat message

src/app.scss

@@ -109,3 +109,12 @@ $modal-background-background-color-dark: rgba($dark, 0.86) !default; // remove t
   position: sticky;
   top: 1rem;
 }
+
+/* Loading chat messages */
+.is-loading {
+  opacity: 0.5;
+  @include loader;
+  width: 1.5rem;
+  height: 1.5rem;
+  border-width: 0.25em;
+}

src/lib/Chat.svelte

@@ -489,7 +489,11 @@
 {/each}
 
 {#if updating}
-  <progress class="progress is-small is-dark" max="100" />
+  <article class="message is-success assistant-message">
+    <div class="message-body content">
+      <span class="is-loading" />
+    </div>
+  </article>
 {/if}
 
 <form class="field has-addons has-addons-right is-align-items-flex-end" on:submit|preventDefault={() => submitForm()}>