Files app: Format dialog spacing and close button

Change the spacing between the last form field and the buttons in the
bottom. Reduce from 44px (24px from form field margin-bottom and 20px
from buttons padding-top). Add 2px padding-bottom for the field because
it was cutting the focus ring.

Remove the close icon by removing the attribute show-close-button in
<cr-dialog>.

This change affects both styles FilesNG and non-NG, since these are
minor, it shouldn't be a problem.

Bug: 992827
Change-Id: I8afc5beb92536d90ddbc007903d7d860edcc59cf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2224741
Commit-Queue: Noel Gordon <noel@chromium.org>
Auto-Submit: Luciano Pacheco <lucmult@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#773923}

ui/file_manager/file_manager/foreground/elements/files_format_dialog.html

@@ -26,6 +26,15 @@
         margin-bottom: var(--cr-form-field-bottom-spacing);
       }
 
+      [slot='body'] > #disk-format {
+        margin-bottom: 0;
+        padding-bottom: 2px;
+      }
+
+      [slot='button-container']  {
+        padding-top: 32px;
+      }
+
       #warning-icon {
         --iron-icon-fill-color: var(--google-red-600);
       }
@@ -45,8 +54,7 @@
       }
     </style>
 
-    <cr-dialog id="dialog" show-close-button
-        close-text="[[i18n('CLOSE_LABEL')]]" >
+    <cr-dialog id="dialog" close-text="[[i18n('CLOSE_LABEL')]]">
       <div slot="title">
         [[i18n('FORMAT_DIALOG_TITLE', volumeInfo_.label)]]
       </div>