Webhook integration/e2e tests don't run on GKE (disabled on all but kind)

[shaneutt]

Current Behavior

When we originally wrote the webhook integration and e2e tests a hack was used to make them work in the kind environment. These tests do not work against other cluster implementations that are now provided by our testing framework, such as GKE due to these hacks.

Expected Behavior

The webhook integration and e2e tests should be able to run on any backend Cluster type that KTF supports.

Steps To Reproduce

1. create a GKE cluster in KTF
2. run the integration tests with the GKE cluster
3. run the e2e tests with the GKE cluster

Kong Ingress Controller version

v2.0.0-alpha.2

Kubernetes version

v1.20.5

Anything else?

• remove the t.Skip() that was put in place in the tests when the cluster.Type() != "kind"

[mflendrich]

Our current tests running on kind cover the functional area, so this is a debt item with little current practical implications, but setting a bad quality precedent.