Disable node affinity e2e test

[sdudoladov]

The test is accountable for the majority of recent e2e test failures run by GitHub Actions (9 out of 12 I've looked into).
The same failure occurs in local runs, though more rarely.

The test fails at various places not showing any immediately obvious pattern. It might be subject to transient kind issues with manipulating k8s objects. We already hit such problems in our e2e test pipeline before,e.g. in earlier kind versions pod deletion lasted for several minutes causing frequent test timeouts.

This PR disables the test to uncover further issues with e2e tests.

[zalando-robot]

Docker image "registry-write.opensource.zalan.do/acid/postgres-operator-ui-test:d3fcc66-pr-1307-1" is not based on an approved base image. Currently, this will have no impact on your deployments, but builds using non-allowed images will be blocked from deployment from February 1st 2021.

To create a compliant Docker image of your application, you must reference an allowed Docker image as its base image in your Dockerfile. This base image must come from the Open Source Registry namespace library and use a recommended version as listed in the documentation.

[zalando-robot]

Docker image "registry-write.opensource.zalan.do/acid/postgres-operator-ui-test:v1.6.0-14-g51b8c3f8-pr-1307-2" is not based on an approved base image. Currently, this will have no impact on your deployments, but builds using non-allowed images will be blocked from deployment from February 1st 2021.

To create a compliant Docker image of your application, you must reference an allowed Docker image as its base image in your Dockerfile. This base image must come from the Open Source Registry namespace library and use a recommended version as listed in the documentation.