Introduce hashicorp/go-metrics compatibility to the SDK module

[mkeeler]

Description

This updates the sdk module to have dual compatibility with both armon/go-metrics and hashicorp/go-metrics

Compatability is attained with build tags

Using tag armonmetrics or no tag at all will result in the library utilizing github.com/armon/go-metrics for metrics emission

Using tag hashicorpmetrics will result in the library utilizing the updated github.com/hashicorp/go-metrics for metrics emission.

For now this will result in no functional changes to Vault with all metrics still flowing out via armon/go-metrics. Eventually, once all HashiCorp libraries have been updated to have dual compat, Vault and other products/services/applications will be PR'ed to switch them over to using hashicorp/go-metrics. This will include updating the build system to use the hashicorpmetrics functionality.

RFC

TODO only if you're a HashiCorp employee

• Backport Labels: If this fix needs to be backported, use the appropriate backport/ label that matches the desired release branch. Note that in the CE repo, the latest release branch will look like backport/x.x.x, but older release branches will be backport/ent/x.x.x+ent.
  • LTS: If this fixes a critical security vulnerability or severity 1 bug, it will also need to be backported to the current LTS versions of Vault. To ensure this, use all available enterprise labels.
• ENT Breakage: If this PR either 1) removes a public function OR 2) changes the signature
  of a public function, even if that change is in a CE file, double check that
  applying the patch for this PR to the ENT repo and running tests doesn't
  break any tests. Sometimes ENT only tests rely on public functions in CE
  files.
• Jira: If this change has an associated Jira, it's referenced either
  in the PR description, commit message, or branch name.
• RFC: If this change has an associated RFC, please link it in the description.
• ENT PR: If this change has an associated ENT PR, please link it in the
  description. Also, make sure the changelog is in this PR, not in your ENT PR.

[github-actions]

Build Results:
Build failed for these jobs: test-containers:failure. Please refer to this workflow to learn more: https://github.com/hashicorp/vault/actions/runs/12814994508

[github-actions]

CI Results:
All Go tests succeeded! ✅

[mkeeler]

A few questions for the Vault team:

1. My branch is up to date with Vault main and the linter still thinks my protobufs are out of date? Is this something I need to fix?
2. Should a changelog entry be added as this PR only affects the SDK module and makes no functional or behavioral change to Vault itself?
3. Presumably I should add the pr/no-milestone label to appease the milestone checker but I would like verification before I do that.