chore: Migrate validating webhook to kustomize

[shorim]

Description

Changes proposed in this pull request (what was done and why):

• Let the validating webhook be created by Kustomize and the operator is responsible only for updating it with the CA bundle
• Remove the deletion of validating webhook when Telemetry CR is being deleted, because the validating webhook should now be cleaned up by the lifecycle-manager instead of the Telemetry reconciler
• Since the name of the validating webhook is changed from validation.webhook.telemetry.kyma-project.io to telemetry-validating-webhook.kyma-project.io, the old validating webhook is deleted in the Telemetry reconciler
• For updating the LogPipeline CRD with conversion webhook, use an update request instead of patch request for simplicity and making it consistent with updating the validating webhook with CA bundle
• Adjust unit and e2e tests

Changes refer to particular issues, PRs or documents:

• Migrate // +kubebuilder:default annotations to a defaulting webhook #1541

Traceability

• The PR is linked to a GitHub issue.
• The follow-up issues (if any) are linked in the Related Issues section.
• If the change is user-facing, the documentation has been adjusted.
• If a CRD is changed, the corresponding Busola ConfigMap has been adjusted.
• The feature is unit-tested.
• The feature is e2e-tested.

[kyma-bot]

New changes are detected. LGTM label has been removed.