CI: Rename RAN-SA-2x2-Module-CN5G pipeline

RAN-SA-2x2-Module-CN5G performs tests not only with 2x2 but also with a 4x4 MIMO
configuration. The pipeline name has been generalized to RAN-SA-Multi-Antenna-CN5G
to cover multiple antenna configurations.

ci-scripts/Jenkinsfile-GitLab-Container

@@ -703,11 +703,11 @@ pipeline {
             }
           }
         }
-        stage ("SA-2x2-Module-CN5G") {
+        stage ("SA-Multi-Antenna-CN5G") {
           when { expression {do5Gtest} }
           steps {
             script {
-              triggerSlaveJob ('RAN-SA-2x2-Module-CN5G', 'SA-2x2-Module-CN5G')
+              triggerSlaveJob ('RAN-SA-Multi-Antenna-CN5G', 'SA-Multi-Antenna-CN5G')
             }
           }
           post {
@@ -715,13 +715,13 @@ pipeline {
               script {
                 // Using a unique variable name for each test stage to avoid overwriting on a global variable
                 // due to parallel-time concurrency
-                saTDD2x2Status = finalizeSlaveJob('RAN-SA-2x2-Module-CN5G')
+                saMultiAntennaStatus = finalizeSlaveJob('RAN-SA-Multi-Antenna-CN5G')
               }
             }
             failure {
               script {
                 currentBuild.result = 'FAILURE'
-                failingStages += saTDD2x2Status
+                failingStages += saMultiAntennaStatus
               }
             }
           }