[breadcrumb] Flip caret image in RTL with transform scaleX

Change caret image RTL transform CSS rotate(-180deg) to scaleX(-1) for
the same visual result.

Bug: 1035691
Change-Id: I3140cc2356118b27cced786fbad335bab2d6ea6e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2094903Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Reviewed-by: Alex Danilo <adanilo@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748459}

ui/file_manager/file_manager/foreground/js/ui/breadcrumb.js

@@ -33,7 +33,7 @@ const breadCrumbTemplate = `
     }
 
     :host-context(html[dir='rtl']) span.caret {
-      transform: rotate(-180deg);
+      transform: scaleX(-1);
     }
 
     button {