Upgrade venctl to a version which supports Helm v4, to fix the E2E tests

[wallrj-cyberark]

Stacked on #759

Upgrade to latest version of venctl, which supports Helm v4

Testing

• https://github.com/jetstack/jetstack-secure/actions/runs/21258654035/job/61180210554?pr=760

I also ran the ark E2E test, to check the hack for the Helm v4 bug.

$ make ark-test-e2e
...
{"ts":1769104182587.7227,"caller":"agent/run.go:420","msg":"Data sent successfully","v":0,"logger":"Run.gatherAndOutputData.postData"}
process_cpu_seconds_total 0.3
process_max_fds 2.147483584e+09
process_network_receive_bytes_total 382493
process_network_transmit_bytes_total 234909
process_open_fds 13
process_resident_memory_bytes 4.974592e+07
process_start_time_seconds 1.76910417713e+09
process_virtual_memory_bytes 1.300307968e+09
process_virtual_memory_max_bytes 1.8446744073709552e+19
/ko-app/ark agent -c /etc/disco-agent/config.yaml --machine-hub --logging-format=json --enable-metrics --enable-pprof --log-level=6