Recover x-pack Packetbeat packaging in 7.x (#23538)

* Recover x-pack packetbeat build in packaging job, commented-out by mistake in #23142.
* Enable x-pack/packetbeat in the CI (backport #22252)

Co-authored-by: Victor Martinez <victormartinezrubio@gmail.com>

.ci/packaging.groovy

@@ -112,7 +112,7 @@ pipeline {
                    'x-pack/heartbeat',
                   // 'x-pack/journalbeat',
                   'x-pack/metricbeat',
-                  // 'x-pack/packetbeat',
+                  'x-pack/packetbeat',
                   'x-pack/winlogbeat'
                 )
               }

Jenkinsfile.yml

@@ -16,11 +16,11 @@ projects:
     - "x-pack/functionbeat"
     - "x-pack/libbeat"
     - "x-pack/metricbeat"
+    - "x-pack/packetbeat"
     - "x-pack/winlogbeat"
     - "dev-tools"
     ##- "x-pack/heartbeat"    It's not yet in the 1.0 pipeline.
     ##- "x-pack/journalbeat"  It's not yet in the 1.0 pipeline.
-    ##- "x-pack/packetbeat"   It's not yet in the 1.0 pipeline.
 
 ## Changeset macros that are defined here and used in each specific 2.0 pipeline.
 changeset: