Correctly align the xfaLayer content with horizontal scrolling/spread modes (issue 13605)

This extends the approach in PRs 12848 and 13606 to also apply to the `xfaLayer`, since otherwise XFA forms will be similarly broken in most non-default scroll/spread modes.

Author: Snuffleupagus

web/xfa_layer_builder.css

@@ -19,6 +19,7 @@
 
 .xfaLayer {
   position: absolute;
+  text-align: initial;
   top: 0;
   left: 0;
   z-index: 200;