chore: Add instance type offering availability to metrics

[jonathan-innis]

Fixes #2596

Description

Adds a metric to our CloudProvider metrics to track the offering availability over time. This also updates the karpenter_cloudprovider_instance_type_price_estimate metric to be fired when the offerings are created, rather than when the prices are updated in the pricing provider. This also changes the name to include the word "offering" to be karpenter_cloudprovider_instance_type_offering_price_estimate to align with karpenter_cloudprovider_instance_type_offering_available

How was this change tested?

make presubmit

Does this change impact docs?

• Yes, PR includes docs updates
• Yes, issue opened: #
• No

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

[netlify]

✅ Deploy Preview for karpenter-docs-prod ready!

Name	Link
🔨 Latest commit	1190499
🔍 Latest deploy log	https://app.netlify.com/sites/karpenter-docs-prod/deploys/65e638ff195b070007858e4b
😎 Deploy Preview	https://deploy-preview-5771--karpenter-docs-prod.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[coveralls]

Pull Request Test Coverage Report for Build 8147053298

Details

• 18 of 18 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.02%) to 82.639%

---

Totals
Change from base Build 8146289356:	-0.02%
Covered Lines:	5255
Relevant Lines:	6359

---

💛 - Coveralls

[jonathan-innis]

/karpenter snapshot

[github-actions]

Snapshot successfully published to oci://021119463062.dkr.ecr.us-east-1.amazonaws.com/karpenter/snapshot/karpenter:0-548f9f5e0e89bf9b14d6cf6326a037c80d7121b6.
To install you must login to the ECR repo with an AWS account:

aws ecr get-login-password --region us-east-1 | docker login --username AWS --password-stdin 021119463062.dkr.ecr.us-east-1.amazonaws.com

helm upgrade --install karpenter oci://021119463062.dkr.ecr.us-east-1.amazonaws.com/karpenter/snapshot/karpenter --version "0-548f9f5e0e89bf9b14d6cf6326a037c80d7121b6" --namespace "kube-system" --create-namespace \
  --set "settings.clusterName=${CLUSTER_NAME}" \
  --set "settings.interruptionQueue=${CLUSTER_NAME}" \
  --set controller.resources.requests.cpu=1 \
  --set controller.resources.requests.memory=1Gi \
  --set controller.resources.limits.cpu=1 \
  --set controller.resources.limits.memory=1Gi \
  --wait

[engedaam]

LGTM 🚀