fix(DAV): Migrate known exceptions to Sabre exceptions when copying

[nickvergessen]

• Found while writing tests for fix(wrapper): Correctly handle directories files_accesscontrol#522

Steps

1. Create a file/folder
2. Set up access control so you can not access the item
3. Try to copy it

Expected (After)

403 Forbidden

<?xml version="1.0" encoding="utf-8"?>
<d:error xmlns:d="DAV:" xmlns:s="http://sabredav.org/ns" xmlns:o="http://owncloud.org/ns">
  <s:exception>OCA\DAV\Connector\Sabre\Exception\Forbidden</s:exception>
  <s:message>Access denied</s:message>
  <o:retry xmlns:o="o:">false</o:retry>
  <o:reason xmlns:o="o:">Access denied</o:reason>
</d:error>

Actual (Before)

500 Internal Server Error

<?xml version="1.0" encoding="utf-8"?>
<d:error xmlns:d="DAV:" xmlns:s="http://sabredav.org/ns">
  <s:exception>OCP\Files\ForbiddenException</s:exception>
  <s:message>Access denied</s:message>
</d:error>

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[nickvergessen]

/backport to stable29

[nickvergessen]

/backport to stable28

[nickvergessen]

/backport to stable27

[julien-nc]

lgtm