tls: fix incomplete mTLS config in conn reuse and session cache

tls: fix incomplete mTLS config in conn reuse and session cache

cert_type, key, key_type, key_passwd and key_blob lived in
ssl_config_data but not in ssl_primary_config, so they were invisible to
match_ssl_primary_config() and to the TLS session cache peer key.

Two easy handles sharing a connection pool could reuse each other's
authenticated connections when they differed only on SSLKEY, SSLKEYTYPE,
KEYPASSWD, SSLCERTTYPE or SSLKEYBLOB. The second handle would silently
inherit the first handle's authenticated identity.

Promote all five fields into ssl_primary_config so the conn-reuse
predicate and session cache key cover the complete client credential
set. Also replace the fixed ":CCERT" session cache marker with the
actual clientcert path so sessions are not shared across different
client certificates.

Verified by test 3303 and 3304

Reported-By: Joshua Rogers (AISLE Research)
Closes #21667