fix: print TLS connection information before HTTP request headers

[AdamMagued]

When logging outgoing HTTP traffic with TLS enabled, TLS connection details and server certificates were printed after the request headers block during the response phase.

This change adjusts RoundTrip logging:

• When TLS logging is enabled, outgoing request header and body formatting are buffered prior to executing the round trip.
• Once the round trip completes and TLS connection state is established, TLS connection details and server certificate info are printed before the request header block, matching the chronological order used on incoming server traffic.
• If a connection error occurs before response receipt, the buffered request headers and error message are emitted as before.
• Updated golden test fixtures in testdata/log.txtar.
• Added TestOutgoingTLSPrintOrder to verify the printing order across NoBuffer, OnReady, and OnEnd flush strategies.

Fixes #1