(css) Improve Sieve filter editor layout

UI/WebServerResources/scss/components/pseudo-input/pseudo-input.scss

@@ -40,6 +40,9 @@
   font-weight: $sg-font-regular;
   line-height: $sg-line-height-1;
   transform: scale($input-label-float-scale);
+}
+
+.pseudo-input-label {
   @include rtl(transform-origin, left top, right top);
 }
 
@@ -47,6 +50,10 @@
   @include rtl(transform-origin, left center, right center);
 }
 
+.button-label--right {
+  @include rtl(transform-origin, right center, left center);
+}
+
 .pseudo-input-label--no-margin,
 .button-label {
   margin-top: 0;