The failover prober cuts upstream_url at /v1, but Load kept the path, so
an upstream_url ending in /v1 probed healthy while every request went to
/v1/v1/... and got a 404, which never trips the target. Cut the path at
/v1 in Load too, with a warning.
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>