fix(cloud): make HasClusterID() return true to silence deprecation warning

[arbianshkodra]

What

Changes HasClusterID() in hcloud/cloud.go from returning false to returning true, and updates the corresponding test in hcloud/cloud_test.go.

Why

The kubernetes/cloud-provider library deprecated --allow-untagged-cloud and emits a startup warning whenever the flag is set:

Flag --allow-untagged-cloud has been deprecated, This flag is deprecated and will be removed in a future release. A cluster-id will be required on cloud instances.

For Hetzner, no ClusterID is ever consumed by the cloud provider — confirmed in #1119:

We don't use cluster-ids anywhere in the code. Neither has allow-untagged-cloud any relevance for us. ... You can safely ignore this message from the logs. We may want to update our code here and don't emit any messages.
— @lukasmetzner

Because HasClusterID() was hardcoded to false, operators were forced to pass --allow-untagged-cloud just to clear the fail-fast check in main.go:73-80, which then triggered the deprecation warning. The flag was functionally a no-op for Hetzner, but its presence was what caused the warning.

Returning true here states the truth (Hetzner does not use ClusterID; treats every cluster as "tagged enough" for its purposes) and lets operators omit the flag entirely. The deprecation warning goes away at its source — kubernetes/cloud-provider only emits it when the flag is set.

Behavior change

Before	After
Operator must set --allow-untagged-cloud or HCCM crashes on startup	Operator can omit the flag
Deprecation warning fires when the flag is set (every install today)	No warning fires when the flag is omitted
HasClusterID() returns false (untruthful: Hetzner doesn't have or want a ClusterID, but the false return implies it should have one)	HasClusterID() returns true (truthful: Hetzner is "tagged enough" for its own purposes)

Operators who keep --allow-untagged-cloud set will continue to see the deprecation warning (because the upstream library still notices the flag) — but they no longer need the flag.

Testing

• go build ./... passes
• go test ./hcloud/ -run TestCloud passes (test updated to assert the new expected behavior with a comment referencing HCCM: "--allow-untagged-cloud=false" and cluster labeling / tagging #1119)
• Verified locally against a Hetzner cluster running v1.31.0 by patching the binary: with the flag dropped from helm values, pod comes up Ready and no deprecation warning is logged.

Closes #1119