Fix simulator response for Dialogflow v1

Change-Id: I0bf05d05d53ef4468d97939f37ac5ffe28a1b132

src/service/dialogflow/_test/conv.v1.test.ts

@@ -136,7 +136,7 @@ test('conv.serialize w/ simple response has fulfillmentText when from simulator'
         },
       },
     },
-    displayText: response,
+    speech: response,
   })
 })
 
@@ -164,7 +164,7 @@ test('conv.serialize w/ simple response text has fulfillmentText when from simul
         },
       },
     },
-    displayText: text,
+    speech: text,
   })
 })
 
@@ -194,7 +194,7 @@ test('conv.serialize w/ two simple responses has fulfillmentText warning for sim
         },
       },
     },
-    displayText: 'Cannot display response in Dialogflow simulator. ' +
+    speech: 'Cannot display response in Dialogflow simulator. ' +
       'Please test on the Google Assistant simulator instead.',
   })
 })
@@ -232,7 +232,7 @@ test('conv.serialize w/ solo helper has fulfillmentText warning for simulator',
         },
       },
     },
-    displayText: 'Cannot display response in Dialogflow simulator. ' +
+    speech: 'Cannot display response in Dialogflow simulator. ' +
       'Please test on the Google Assistant simulator instead.',
   })
 })
@@ -298,7 +298,7 @@ test('conv.serialize w/ non solo helper has fulfillmentText warning for simulato
         },
       },
     },
-    displayText: 'Cannot display response in Dialogflow simulator. ' +
+    speech: 'Cannot display response in Dialogflow simulator. ' +
       'Please test on the Google Assistant simulator instead.',
   })
 })
@@ -336,7 +336,7 @@ test('conv.serialize w/ image has fulfillmentText warning for simulator', t => {
         },
       },
     },
-    displayText: 'Cannot display response in Dialogflow simulator. ' +
+    speech: 'Cannot display response in Dialogflow simulator. ' +
       'Please test on the Google Assistant simulator instead.',
   })
 })

src/service/dialogflow/conv.ts

@@ -387,7 +387,9 @@ export class DialogflowConversation<
       }
       if (simulator && payload) {
         const items = payload.google.richResponse.items!
-        response.displayText =
+        // Simulator only shows speech response
+        // Since this is only shown to the simulator as text, the speech is the displayText
+        response.speech =
           (payload.google.systemIntent || items.length > 1) ?
           SIMULATOR_WARNING :
           (items[0].simpleResponse!.displayText ||