[Custom Agents] Return the policy name also for 9.x stacks

[mrodm]

This PR fixes the policy name used in Custom Agents (Deprecated). with-custom and system-flags steps in Buildkite.

The method needs to take into account also 9.x Elastic stacks.

This should just affect Custom Agents since in the other scenarios Elastic Agents are setup via Independent Elastic Agents (agentdeployer module).

Relates #2758

How to test this PR locally

cd test/packages/with-custom-agent/auditd_manager/
elastic-package stack up -v -d --version 9.0.3

# This command should finish successfully
elastic-package test system -v

elastic-package stack down -v

• Tested custom-agent step with 9.0.3 Elastic stack: https://buildkite.com/elastic/elastic-package/builds/5741#01983359-45ee-45ae-b01a-43c9e23554f2

[mrodm]

test integrations

[elastic-vault-github-plugin-prod]

Created or updated PR in integrations repository to test this version. Check elastic/integrations#14653

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 78d6971

History

• 💔 Build #5741 failed a2390d6

cc @mrodm

[mrodm]

Similar to the one defined in agentdeployer module.

elastic-package/internal/agentdeployer/kubernetes.go

Lines 258 to 263 in 2f30958

	func getTokenPolicyName(stackVersion, policyName string) string {
	if strings.HasPrefix(stackVersion, "7.") {
	return ""
	}
	return policyName
	}

[jsoriano]

Good one, thanks!