Update v1.4 conformance tests implementation flags

[ciarams87]

The nightly conformance tests running against the main Gateway API repo are failing.

This is due to a change in the test suite setup -> kubernetes-sigs/gateway-api#3715

This will need to be fixed before the next Gateway API release

[sjberman]

This seems like something we could even fix before updating to 1.4.

[sjberman]

Closing, the change in Gateway API was reverted.