[3.1.6 Backport] Tweak logging around import of JSON but not JSON object docs

CB Server document data types are determined based on whether the body is valid JSON. This includes non-object JSON types, like arrays, strings, numbers.

Documents that CB Server determined was not a binary data type, but are also not a JSON object (e.g. arrays, numbers, strings) are handled differently by SG import than just binary documents.

CBG-3332 made SG warn when encountering a JSON data type document that is not a JSON object appear over DCP, even if there is no pre-existing _sync metadata present with a misleading log message.

• For true binary (non-JSON) docs (MemcachedDataTypeRaw):
  • Nothing required. Existing info loging covers.
• For JSON but not JSON object docs:
  • If no existing _sync data present:

• • • Similar info log to describe why we're not importing this document.
    • It's valid that customers have counter documents, etc. that they don't ever want importing by SG.
  • If there is _sync data present:

• • • Detect this case and continue to warn.
    • Implies the document should be mobile-aware but can no longer be (because of the body being changed to something other than a JSON object)
    • Sync metadata should be removed from the document if it is no longer needed for CB Mobile.