Update inputset default_on_pr_input

Author: yakov-g

.harness/pipelines/test_functional_by_framework_multisteps/input_sets/default_on_pr_input.yaml

@@ -12,7 +12,7 @@ inputSet:
         value: datarobot-user-models
       - name: target_branch
         type: String
-        value: <<+trigger.targetBranch>
+        value: <+trigger.targetBranch>
       - name: source_branch
         type: String
         value: <+trigger.sourceBranch>