Viewing preview URL logs out current user

[emteknetnz]

When you follow a shared draft link and you are logged in, it will logged you out.

This was identified via this issue: https://github.com/silverstripe/silverstripe-sharedraftcontent/pull/153#issuecomment-1050699391

This appears to clash with Session::$strict_user_agent_check (on by default), the session is invalidated on viewing a preview/ URL due to the change in UA string.

ACs

• [x] When following a shared draft link the user remains logged in
• [x] The previous bugfix remains in place

PR

• https://github.com/silverstripe/silverstripe-sharedraftcontent/pull/168

[sabina-talipova]

Close prior PR. Had issues with unexpected commits after rebase. Open new PR https://github.com/silverstripe/silverstripe-sharedraftcontent/pull/168

[GuySartorelli]

Linked pr is merged.