replace global vault handlers with newVaultHandlers()

[thyton]

Description

This PR addresses the data race caused by #27394 after merged into the ENT repo

 =============== test-go (4) ===========================
WARNING: DATA RACE
Write at 0x00c002d54180 by goroutine 63655:
  runtime.mapassign_faststr()
      /home/runner/actions-runner/_work/_tool/go/1.22.4/x64/src/runtime/map_faststr.go:203 +0x0
  maps.Copy[go.shape.map[string]github.com/hashicorp/vault/sdk/physical.Factory,go.shape.map[string]github.com/hashicorp/vault/sdk/physical.Factory,go.shape.string,go.shape.func(map[string]string, github.com/hashicorp/go-hclog.Logger) (github.com/hashicorp/vault/sdk/physical.Backend, error)]()
      /home/runner/actions-runner/_work/_tool/go/1.22.4/x64/src/maps/maps.go:55 +0x167
  github.com/hashicorp/vault/command.extendAddonCommands()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/commands_full.go:94 +0x36
  github.com/hashicorp/vault/command.initCommands()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/commands.go:175 +0x56
  github.com/hashicorp/vault/command.RunCustom()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/main.go:225 +0xfee
  github.com/hashicorp/vault/command.execPKIVerifyNonJson()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/pki_verify_sign_test.go:150 +0x2d6
  github.com/hashicorp/vault/command.execPKIVerifyJson()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/pki_verify_sign_test.go:131 +0x92
  github.com/hashicorp/vault/command.runPkiListIntermediateTests()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/pki_list_intermediate_test.go:211 +0x212a
  github.com/hashicorp/vault/command.TestPKIListIntermediate()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/pki_list_intermediate_test.go:36 +0x7a
  testing.tRunner()
      /home/runner/actions-runner/_work/_tool/go/1.22.4/x64/src/testing/testing.go:1689 +0x21e
  testing.(*T).Run.gowrap1()
      /home/runner/actions-runner/_work/_tool/go/1.22.4/x64/src/testing/testing.go:1742 +0x44

Previous write at 0x00c002d54180 by goroutine 63654:
  runtime.mapassign_faststr()
      /home/runner/actions-runner/_work/_tool/go/1.22.4/x64/src/runtime/map_faststr.go:203 +0x0
  maps.Copy[go.shape.map[string]github.com/hashicorp/vault/sdk/physical.Factory,go.shape.map[string]github.com/hashicorp/vault/sdk/physical.Factory,go.shape.string,go.shape.func(map[string]string, github.com/hashicorp/go-hclog.Logger) (github.com/hashicorp/vault/sdk/physical.Backend, error)]()
      /home/runner/actions-runner/_work/_tool/go/1.22.4/x64/src/maps/maps.go:55 +0x167
  github.com/hashicorp/vault/command.extendAddonCommands()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/commands_full.go:94 +0x36
  github.com/hashicorp/vault/command.initCommands()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/commands.go:175 +0x56
  github.com/hashicorp/vault/command.RunCustom()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/main.go:225 +0xfee
  github.com/hashicorp/vault/command.createComplicatedIssuerSetUpWithIssueIntermediate()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/pki_issue_intermediate_test.go:151 +0x1653
  github.com/hashicorp/vault/command.TestPKIIssueIntermediate()
      /home/runner/actions-runner/_work/vault-enterprise/vault-enterprise/command/pki_issue_intermediate_test.go:35 +0x6b
  testing.tRunner()
      /home/runner/actions-runner/_work/_tool/go/1.22.4/x64/src/testing/testing.go:1689 +0x21e
  testing.(*T).Run.gowrap1()
      /home/runner/actions-runner/_work/_tool/go/1.22.4/x64/src/testing/testing.go:1742 +0x44

The PR replaces all global vault handlers in commands.go with newVaultHandlers() that returns *vaultHandlers struct that encapsulates all vault handlers. https://github.com/hashicorp/vault-enterprise/pull/6084's been created to test and address the issue in the ENT repo.

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Build Results:
All builds succeeded! ✅

[github-actions]

CI Results:
All Go tests succeeded! ✅