Support for Kubernetes v1.31

[ialidzhikov]

How to categorize this PR?

/area open-source usability /kind enhancement /platform openstack /exp intermediate /topology garden seed shoot /merge squash

What this PR does / why we need it: This PR adds support for Kubernetes 1.31 to the extension.

Which issue(s) this PR fixes: Part of https://github.com/gardener/gardener/issues/10286

Special notes for your reviewer:

• I have successfully validated the functionality as follows:
  • :white_check_mark: Create new clusters with versions < 1.31
  • :white_check_mark: Create new clusters with version = 1.31
  • :white_check_mark: Upgrade old clusters from version 1.30 to version 1.31
  • :white_check_mark: Delete clusters with versions < 1.31
  • :white_check_mark: Delete clusters with version = 1.31

Release note:

The provider-openstack extension does now support shoot clusters with Kubernetes version 1.31. You should consider the [Kubernetes release notes](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG/CHANGELOG-1.31.md) before upgrading to 1.31. 

[gardener-robot]

@ialidzhikov You need rebase this pull request with latest master branch. Please check.