add instruction to error output

src/views/DiscoverView.vue

@@ -223,7 +223,7 @@ export default class DiscoverView extends Vue {
 
       if (!identity) {
         throw new Error(
-          "An ID is chosen but there are no keys for it so it cannot be used to talk with the service.",
+          "An ID is chosen but there are no keys for it so it cannot be used to talk with the service. Switch your ID.",
         );
       }
 

src/views/HomeView.vue

@@ -353,7 +353,7 @@ export default class HomeView extends Vue {
 
       if (!identity) {
         throw new Error(
-          "An ID is chosen but there are no keys for it so it cannot be used to talk with the service.",
+          "An ID is chosen but there are no keys for it so it cannot be used to talk with the service. Switch your ID.",
         );
       }
 

src/views/NewEditProjectView.vue

@@ -220,7 +220,7 @@ export default class NewEditProjectView extends Vue {
         const identity = await this.getIdentity(this.activeDid);
         if (!identity) {
           throw new Error(
-            "An ID is chosen but there are no keys for it so it cannot be used to talk with the service.",
+            "An ID is chosen but there are no keys for it so it cannot be used to talk with the service. Switch your ID.",
           );
         }
         this.LoadProject(identity);