Fix beats serverless tests and enable them in all CI builds (#4501)

* Fix serverless packages
* enable beats serverless tests for all CI builds

Author: pchila

.buildkite/pipeline.yml

@@ -246,7 +246,7 @@ steps:
   - label: "Serverless Beats Tests"
     key: "serverless-beats-integration-tests"
     command: ".buildkite/scripts/steps/beats_tests.sh"
-    if: "build.env('CRON') == 'yes'"
+    # if: "build.env('CRON') == 'yes'"
     agents:
       provider: "gcp"
       machineType: "n1-standard-8"

pkg/testing/runner/runner.go

@@ -466,7 +466,7 @@ func (r *Runner) getBuilds(b OSBatch) []Build {
 		var serverlessPackages []string
 		for _, p := range packages {
 			if slices.Contains([]string{"targz", "zip"}, p) {
-				packages = append(packages, p)
+				serverlessPackages = append(serverlessPackages, p)
 			}
 		}
 		packages = serverlessPackages