Bump Kubernetes dependencies to v0.26.4

[MartinWeindel]

How to categorize this PR?

/area control-plane
/kind bug

What this PR does / why we need it:
Update Kubernetes dependencies (especially k8s.io/client-go) from v0.26.3 to v0.26.4 to resolve panic on working with special shoots.
As a consequence the gardenlet is crashing all the time if it runs as leader.

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x12e9630]

goroutine 29665 [running]:
k8s.io/client-go/discovery.convertAPIResource(...)
	/go/src/github.com/gardener/gardener/vendor/k8s.io/client-go/discovery/aggregated_discovery.go:114
k8s.io/client-go/discovery.convertAPIGroup({{{0x0, 0x0}, {0x0, 0x0}}, {{0xc0922dad20, 0x15}, {0x0, 0x0}, {0x0, 0x0}, ...}, ...})
	/go/src/github.com/gardener/gardener/vendor/k8s.io/client-go/discovery/aggregated_discovery.go:95 +0x6d0
k8s.io/client-go/discovery.SplitGroupsAndResources({{{0xc08f9f7638, 0x15}, {0xc08fb7d1e0, 0x1b}}, {{0x0, 0x0}, {0x0, 0x0}, {0x0, 0x0}, ...}, ...})
	/go/src/github.com/gardener/gardener/vendor/k8s.io/client-go/discovery/aggregated_discovery.go:49 +0x118
k8s.io/client-go/discovery.(*DiscoveryClient).downloadAPIs(0x5555?)
	/go/src/github.com/gardener/gardener/vendor/k8s.io/client-go/discovery/discovery_client.go:328 +0x3d8
k8s.io/client-go/discovery.(*DiscoveryClient).GroupsAndMaybeResources(0x2f?)

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:
This fix should also be cherry-picked for the release-v1.78 branch

Release note:

Update Kubernetes dependencies (especially `k8s.io/client-go`) from `v0.26.3` to `v0.26.4` to resolve panic on working with special shoots.

[ialidzhikov]

/lgtm

[gardener-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ialidzhikov

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[gardener-prow]

LGTM label has been added.

Git tree hash: 98172de6e20d308964628ba33f5be0268e8b8fe6

[ialidzhikov]

/test pull-gardener-e2e-kind-ha-single-zone-upgrade

[shafeeqes]

/cherry-pick release-v1.78

[shafeeqes]

/cherry-pick release-v1.77

[shafeeqes]

/cherry-pick release-v1.76

[gardener-ci-robot]

@shafeeqes: new pull request created: #8423

In response to this:

/cherry-pick release-v1.78

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[gardener-ci-robot]

@shafeeqes: new pull request created: #8424

In response to this:

/cherry-pick release-v1.77

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[gardener-ci-robot]

@shafeeqes: new pull request created: #8425

In response to this:

/cherry-pick release-v1.76

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.