fix(dav): Restrict properties allowed object classes

[come-nc]

Summary

Restrict which classes can be serialized by the DAV properties backend.

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)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

[come-nc]

/backport to stable32

[come-nc]

The litmus tests need support for array type it seems:

23. propvalnspace......... 
23. propvalnspace......... FAIL (PROPPATCH of property with value defining namespace)
24. 
<- summary for `props': of 30 tests run: 29 passed, 1 failed. 96.7%

<d:error xmlns:d="DAV:" xmlns:s="http://sabredav.org/ns">
  <s:exception>Sabre\DAV\Exception</s:exception>
  <s:message>Property "{http://example.com/neon/litmus/}valnspace" has an invalid value of type array</s:message>
</d:error>

[AndyScherzinger]

🐘