[B.P. 7.1.5] - [XDCR] Inaccurate logging for explicit mapping

Given XDCR source bucket B1 scope S1 has 2 collections:

col1 and col2

When XDCR has a specific explicit mapping such as:

S1.col1 -> S1.col1

XDCR log will contain message such as:

2023-01-30T21:55:05.040-08:00 WARN GOXDCR.XDCRRouter: current explicit mapping does not include target destination given source scope S1 collection col2 - this mapping may need to be backfilled

This is inaccurate and causes debugging headaches as no backfill is needed as col2 was never requested.