Investigate an possibility to merge sidecars and ambient runs together in downstream pipeline 3.

Currently we are running downstream pipeline 3 twice on all platforms, one for sidecars and one for ambient. Like:

> install operators
> run e2e tests (!ambient or ambient)
> run istio integration (all packages except ambient or all ambient packages)
> install ossm3 + tempo + kiali + ocp monitoring (sidecars or ambient mode)
> kiali integration
> kiali cypress (@core or @ambient tests)
> kiali ossmc (@core or @ambient tests)

The tests for sidecar and ambient modes are mutually exclusive and should be possible to run together.
istio integration and sail e2e tests manage the ControlPlane by themselves, however, the kiali jobs require installing the full stack (ossm, kiali, tempo). (sidecar or ambient) 
Kiali tests themselves are installing demo apps, so different demo apps for sidecar and ambient is not an issue.
So, currently, we need to clean up cluster before running kiali ambient and the downstream pipeline can be changed to:

> install operators
> run e2e tests (all)
> run istio integration (all packages)
> install ossm3 + tempo + kiali + ocp monitoring (sidecars mode)
> kiali integration
> kiali cypress (@core) 
> kiali ossmc (@core)
> clean up env
> install ossm3 + tempo + kiali + ocp monitoring (ambient mode)
> kiali cypress (@ambient) 
> kiali ossmc (@ambient)

A Disadvantage is that cleaning up and installing ossm again can be time-consuming and error-prone.

Or, we can use only ambient mode for istio control plane for install service mesh job and adjust failed kiali cypress tests to expect a little different env, so the pipeline would look like:

> install operators
> run e2e tests (all)
> run istio integration (all packages)
> install ossm3 + tempo + kiali + ocp monitoring (ambient mode)
> kiali integration
> kiali cypress (@core)
> kiali cypress (@ambient) 
> kiali ossmc (@core)
> kiali ossmc (@ambient)

But there is a question of how difficult/time-consuming that would be ( adapt kiali cypress tests for ambient istio cp)

More info in this slack thread: https://redhat-internal.slack.com/archives/C014C8Y0S64/p1761726480173649?thread_ts=1761669796.131279&cid=C014C8Y0S64