REGTESTS: checks: skip tcp-check-client-hello.vtc under FIPS mode

REGTESTS: checks: skip tcp-check-client-hello.vtc under FIPS mode

This test hangs and gets killed after a 10s timeout when run against
an SSL library running in FIPS mode (e.g. AWS-LC-FIPS): backend be1's
check server line uses "curves X25519" to exercise X25519 key-share
routing (group 0x001d), which is rejected at config-parse time by
HAProxy's own FIPS compliance checks (src/fips.c) since X25519 is not
a NIST P-curve. The "h1" haproxy process then fails to start, and
vtest waits on it until its startup timeout kills it with SIGKILL
instead of reporting a clean startup failure.

Skip the test using the fips_mode() config condition predicate.