crosh_builtin: add more permissions

This syncs the set of permissions from Secure Shell that we want/use
in newer versions of hterm.

Bug: 822490, 646690
Change-Id: I7abadb369b3178739808aa41fd0cae9ef3c0759e
Reviewed-on: https://chromium-review.googlesource.com/1061619Reviewed-by: Raymes Khoury <raymes@chromium.org>
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559417}

chrome/browser/resources/chromeos/crosh_builtin/manifest.json

@@ -15,8 +15,10 @@
   "permissions": [
     "clipboardRead",
     "clipboardWrite",
-    "unlimitedStorage",
+    "notifications",
     "storage",
-    "terminalPrivate"
+    "terminalPrivate",
+    "unlimitedStorage",
+    "accessibilityFeatures.read"
   ]
 }