Update getting batch size for cloud deploy and upgrade mcp jobs

Get batch size based on common function which respect all possible ways
of setting batch sizes.

Change-Id: I045814854e92f7267723a5f4bd62509e8c71b71e
Related-Prod: PROD-27850
(cherry picked from commit 9365e2638bc41510ac1f435dfa0ba6acf19eb2d4)
diff --git a/upgrade-mcp-release.groovy b/upgrade-mcp-release.groovy
index 7eb39b1..2770a07 100644
--- a/upgrade-mcp-release.groovy
+++ b/upgrade-mcp-release.groovy
@@ -356,10 +356,7 @@
                 error('Pillar data is broken for Salt master node! Please check it manually and re-run pipeline.')
             }
             if (!batchSize) {
-                def workerThreads = salt.getReturnValues(salt.getPillar(venvPepper, "I@salt:master", "salt:master:worker_threads", null)).toString()
-                if (workerThreads.isInteger() && workerThreads.toInteger() > 0) {
-                   batchSize = workerThreads
-                }
+                batchSize = salt.getWorkerThreads(venvPepper)
             }
 
             stage('Update Reclass and Salt-Formulas') {