[7.6][Transform] blacklist continuous transform tests if upgraded from 7.2.x (#48344)

blacklist continuous transform tests if upgraded from 7.2.x

fixes #48336

Author: Hendrik Muhs

x-pack/qa/rolling-upgrade/build.gradle

@@ -197,9 +197,11 @@ for (Version bwcVersion : bwcVersions.wireCompatible) {
         // Dataframe transforms were not added until 7.2.0
         if (bwcVersion.before('7.2.0')) {
             toBlackList << 'upgraded_cluster/80_data_frame_jobs_crud/Get start, stop, and delete old cluster batch data frame transforms'
+        }
+        // continuous Dataframe transforms were not added until 7.3.0
+        if (bwcVersion.before('7.3.0')) {
             toBlackList << 'upgraded_cluster/80_data_frame_jobs_crud/Test GET, stop, delete, old continuous transforms'
         }
-
         // transform in mixed cluster is effectively disabled till 7.4, see gh#48019
         if (bwcVersion.before('7.4.0')) {
             toBlackList << 'upgraded_cluster/80_data_frame_jobs_crud/Get start, stop mixed cluster batch data frame transforms'