Fix uploading UI

Signed-off-by: Janne Koschinski <janne@kuschku.de>

assets/sass/_page_upload.sass

@@ -100,8 +100,8 @@
                 will-change: left, right
                 animation: indeterminate-short 2.1s cubic-bezier(0.165, 0.84, 0.44, 1) infinite
                 animation-delay: 1.125s
-      &:not(.uploading) .progress
-        opacity: 0
+        &:not(.uploading) .progress
+          opacity: 0
   &.submitted .container.centered
     display: none
   &:not(.submitted) .uploading-images