DCP Data Type is non-JSON for docs containing zero-value JSON numbers with exponent

When creating a document containing a zero-value JSON number using an exponent (E.g: "0e5", or "0e-5"), the document is sent over DCP without a JSON data type flag set.

The document appears to have a JSON data type set correctly in the UI when viewing the document. This issue is just seen in the data type field over DCP.

If the number is non-zero using an exponent (e.g: "0.1e5", or "0.1e-5"), or contains no exponent (e.g. "0.0000") it is correctly interpreted as JSON and sent with the JSON data type.

Issue originally reported here: https://github.com/couchbase/sync_gateway/issues/4508