fix: do not print warning if context injection is already set up

src/commands/stepfunctions/helpers.ts

@@ -150,9 +150,16 @@ check out https://docs.datadoghq.com/serverless/step_functions/troubleshooting/\
     return true
   }
 
+  // context injection is already set up
+  if (step.Parameters['Payload.$'] === 'States.JsonMerge($$, $, false)') {
+    context.stdout.write(` Step ${stepName}: Context injection is already set up. Skipping context injection.\n`)
+
+    return false
+  }
+
   // custom payload
   context.stdout
-    .write(`[Warn] Step ${stepName} has a custom Payload field. Step Functions Context Object injection skipped. \
+    .write(`[Warn] Step ${stepName}: has a custom Payload field. Step Functions Context Object injection skipped. \
 Your Step Functions trace will not be merged with downstream Lambda traces. To manually merge these traces, \
 check out https://docs.datadoghq.com/serverless/step_functions/troubleshooting/\n`)
 
@@ -203,6 +210,13 @@ merge these traces, check out https://docs.datadoghq.com/serverless/step_functio
     return true
   }
 
+  // context injection is already set up
+  if (step.Parameters.Input['CONTEXT.$'] === 'States.JsonMerge($$, $, false)') {
+    context.stdout.write(` Step ${stepName}: Context injection is already set up. Skipping context injection.\n`)
+
+    return false
+  }
+
   context.stdout
     .write(`[Warn] Step ${stepName}'s Parameters.Input field has a custom CONTEXT field. Step Functions Context \
 Object injection skipped. Your Step Functions trace will not be merged with downstream Step Function traces. To \