Fix Button with Loading Labeled Icon bug

Author: flppv

src/definitions/elements/icon.less

@@ -71,15 +71,19 @@ i.icon:before {
 i.icon.loading {
   height: 1em;
   line-height: 1;
+}
+
+i.icon.loading:before {
   animation: icon-loading @loadingDuration linear infinite;
 }
+
 @keyframes icon-loading {
- from {
-    transform: rotate(0deg);
- }
- to {
-    transform: rotate(360deg);
- }
+  from {
+    transform: translateY(-50%) rotate(0deg);
+  }
+  to {
+    transform: translateY(-50%) rotate(360deg);
+  }
 }
 
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