[log] Add connection type to log statement

Summary:
In addition to adding more specificity to the log statement about the type of
connection, this change also consolidates two statements into one. Previously,
the second one should have never been hit, since block-relay connections would
match the "!IsInboundConn()" condition and return early.

This is a backport of core#19725 [1/5]
https://github.com/bitcoin/bitcoin/pull/19725/commits/49c10a9ca40967d28ae16dfea9cccc6f3a6624a1

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D10371