added odd default circle icon size for better visual vertical alignment in firefox

ui/src/components/base/RefreshButton.svelte

@@ -44,7 +44,7 @@
             transform: rotate(180deg);
         }
     }
-    .btn.refreshing i {
+    .btn.refreshing i:before {
         animation: refresh 200ms linear;
     }
 </style>

ui/src/scss/_form.scss

@@ -227,7 +227,16 @@ button {
         border-radius: 50%;
         padding: 0;
         i {
+            $iconSize: 23px;
             font-size: 1.2857rem;
+            text-align: center;
+            width: $iconSize;
+            height: $iconSize;
+            line-height: $iconSize;
+            &:before {
+                margin: 0;
+                display: block;
+            }
         }
         &.btn-sm i,
         &.btn-xs i {