CrOS - Policy - PIN Autosubmit

Update PIN Autosubmit policy to reflect that it only works
with PINs that are between 6 to 12 digits long.

Change-Id: I0979f8da62199832420e787ded4253705b0f3976
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2490521Reviewed-by: Denis Kuznetsov [CET] <antrim@chromium.org>
Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Commit-Queue: Roman Sorokin [CET] <rsorokin@chromium.org>
Auto-Submit: Renato Silva <rrsilva@google.com>
Cr-Commit-Position: refs/heads/master@{#820142}

components/policy/resources/policy_templates.json

@@ -23050,7 +23050,8 @@ If you disable this policy, web page scrolling to specific text fragments via UR
           Instead of showing the same textfield that is used for password input, this
           feature shows a special UI that clearly shows to the user how many
           digits are necessary for their PIN. As a consequence, the user's PIN length
-          will be stored outside the user encrypted data.
+          will be stored outside the user encrypted data. Only supports PINs that are
+          between 6 and 12 digits long.
 
           If this policy is set to false, users will not have the option of enabling
           the feature on the Settings page.''',