Revert "Use SVG icon for files-ng elider button"

This reverts commit e909f808.

Reason for revert: I believe this change broke the breadcrumb elider button drop-down menu. No manual test of this change it seems.

Original change's description:
> Use SVG icon for files-ng elider button
> 
> Bug: 1035691
> Change-Id: I4aac6e02a90dd7e466f937e7f77a928480fb14e5
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2087860
> Commit-Queue: Alex Danilo <adanilo@chromium.org>
> Commit-Queue: Noel Gordon <noel@chromium.org>
> Reviewed-by: Noel Gordon <noel@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#747113}

TBR=noel@chromium.org,adanilo@chromium.org

Change-Id: I8764d88a5cfaf1565abfb14762983a21254b8c41
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1035691
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2089431Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747182}

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

@@ -66,15 +66,6 @@ const breadCrumbTemplate = `
       font-weight: 500;
     }
 
-    button[elider] {
-      -webkit-mask-image: url(../../images/files/ui/menu_ng.svg);
-      -webkit-mask-position: center;
-      -webkit-mask-repeat: no-repeat;
-      background-color: currentColor;
-      min-width: 20px;
-      transform: rotate(90deg);
-    }
-
     button:focus {
       border: 1px solid blue;
       outline: none;