Use standard spinner for gallery loading.

src/scss/gallery.scss

@@ -1,5 +1,3 @@
-@use 'dotdotdot.scss';
-
 :host {
   width: 100%;
   height: auto;
@@ -25,41 +23,6 @@
   display: none;
 }
 
-:host ha-card {
-  min-width: 100%;
-  aspect-ratio: 1/1;
-  display: flex;
-  justify-content: center;
-  align-items: center;
-  box-sizing: border-box;
-  text-align: center;
-  color: var(--primary-text-color, white);
-  border: 1px solid var(--primary-color);
-  border-radius: var(
-    --frigate-card-css-border-radius,
-    var(--ha-card-border-radius, 4px)
-  );
-
-  // Folder background color should match the thumbnail element background
-  // color.
-  background-color: var(--primary-background-color, black);
-  padding: 10px;
-  line-height: 1;
-  overflow: hidden;
-
-  // Some themes override these values (with high CSS specificity) which is
-  // intended for full cards rather than internal ones. Since we use multiple of
-  // these for folders, we cannot use an ID and need to resort to !important.
-  margin: 0px !important;
-  box-shadow: none !important;
-
-  transition: transform 0.2s linear;
-}
-ha-card:hover {
-  transform: scale(1.04);
-}
-
-ha-card,
 frigate-card-thumbnail {
   height: 100%;
   max-height: var(--frigate-card-thumbnail-size);
@@ -67,3 +30,7 @@ frigate-card-thumbnail {
 frigate-card-thumbnail:not([details]) {
   width: 100%;
 }
+frigate-card-progress-indicator {
+  // Progress indicator spans the grid.
+  grid-column: 1 / -1;
+}