Remove GrpcWebSocketListeners from http-advanced-*

[mocenas]

Summary

Remove GrpcWebSocketListeners from http-advanced-*. They are currently unused. There were used before, but tests were changed in #1833 and those listeners are unused since that.

I know some tests are supposed to be reimplemented as part of #1832 but not sure if those listeners are supposed to be part of it. Should we preserve those @michalvavrik ?

Please select the relevant options.

• Bug fix (non-breaking change which fixes an issue)
• Dependency update
• Refactoring
• Backport
• New scenario (non-breaking change which adds functionality)
• This change requires a documentation update
• This change requires execution against OCP (use run tests phrase in comment)

Checklist:

• Methods and classes used in PR scenarios are meaningful
• Commits are well encapsulated and follow the best practices

[michalvavrik]

If we need listeners in the future, we can add them and write them according to what we need.

[mocenas]

OK cc @gtroitsk