chore: Add karpenter.sh/registered label

[jonathan-innis]

Fixes #N/A

Description

• Adds the karpenter.sh/registered label to keep internal data consistency within the Node after all the labels, annotations, and taints have been properly propagated onto the Node after registration

How was this change tested?

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[coveralls]

Pull Request Test Coverage Report for Build 5448973616

• 35 of 43 (81.4%) changed or added relevant lines in 7 files are covered.
• 14 unchanged lines in 5 files lost coverage.
• Overall coverage decreased (-0.1%) to 81.553%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/controllers/machine/lifecycle/registration.go	15	19	78.95%
pkg/controllers/state/statenode.go	14	18	77.78%

Files with Coverage Reduction	New Missed Lines	%
pkg/controllers/provisioning/scheduling/topology.go	2	86.49%
pkg/controllers/provisioning/scheduling/topologygroup.go	2	96.75%
pkg/test/cachesyncingclient.go	2	82.47%
pkg/controllers/node/controller.go	4	70.59%
pkg/test/expectations/expectations.go	4	96.61%

Totals
Change from base Build 5447725988:	-0.1%
Covered Lines:	6994
Relevant Lines:	8576

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 5556670919

• 30 of 34 (88.24%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.05%) to 81.447%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/controllers/machine/lifecycle/registration.go	16	20	80.0%

Totals
Change from base Build 5497223404:	0.05%
Covered Lines:	7015
Relevant Lines:	8613

---

💛 - Coveralls