chore: Remove remaining alpha fields from codebase

[jonathan-innis]

Fixes #N/A

Description

This change removes the remaining alpha field logic handling that's still present in the codebase so that Karpenter only supports the beta APIs moving forward.

How was this change tested?

make presubmit

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 6984745902

• 39 of 41 (95.12%) changed or added relevant lines in 16 files are covered.
• 98 unchanged lines in 9 files lost coverage.
• Overall coverage decreased (-0.6%) to 79.541%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/controllers/provisioning/provisioner.go	1	3	33.33%

Files with Coverage Reduction	New Missed Lines	%
pkg/controllers/provisioning/provisioner.go	1	79.26%
pkg/controllers/state/statenode.go	1	86.09%
pkg/apis/v1alpha5/provisioner_validation.go	2	91.47%
pkg/controllers/disruption/drift.go	2	79.1%
pkg/controllers/nodeclaim/lifecycle/initialization.go	2	90.54%
pkg/utils/nodepool/nodepool.go	2	82.14%
pkg/controllers/provisioning/scheduling/preferences.go	7	86.67%
pkg/apis/v1alpha5/register.go	10	0.0%
pkg/apis/v1alpha5/zz_generated.deepcopy.go	71	0.0%

Totals
Change from base Build 6963402001:	-0.6%
Covered Lines:	8114
Relevant Lines:	10201

---

💛 - Coveralls

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ellistarn, jonathan-innis

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[jonathan-innis]

@ellistarn Need a /lgtm for approval now

[ellistarn]

/lgtm