Add NavigationManager to Switch Access manifest

Bug: None
Change-Id: Idb37b6255dd3c5a5158426544cec48b487fc5945
Reviewed-on: https://chromium-review.googlesource.com/c/1313729Reviewed-by: David Tseng <dtseng@chromium.org>
Commit-Queue: Zach Helfinstein <zhelfins@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605187}

chrome/browser/resources/chromeos/switch_access/manifest.json.jinja2

@@ -12,7 +12,6 @@
   "background": {
     "scripts": [
       "auto_scan_manager.js",
-      "automation_manager.js",
       "switch_access_predicate.js",
       "closure_shim.js",
       "commands.js",
@@ -20,6 +19,7 @@
       "context_menu_manager.js",
       "keyboard_handler.js",
       "message_handler.js",
+      "navigation_manager.js",
       "prefs.js",
       "switch_access.js",
       "tree_walker.js",