fix(questionnaire): answer not persisted

* if two multiselect questions are right after each other the value was
no update due to a missing watch handler

src/components/input-multiple-choice/input-multiple-choice.tsx

@@ -1,4 +1,4 @@
-import { Component, Event, EventEmitter, h, Prop } from '@stencil/core';
+import { Component, Event, EventEmitter, h, Prop, Watch } from '@stencil/core';
 
 @Component({
   styleUrl: 'input-multiple-choice.css',
@@ -10,6 +10,10 @@ export class InputMultipleChoice {
     value: string;
     text: string;
   }[];
+  @Watch('options')
+  onOptionsChanged() {
+    this.updateFormDataHandler(this.inputId, this.getValue());
+  }
   @Prop() value: string[] = undefined;
 
   getValue(): string[] {
@@ -24,6 +28,7 @@ export class InputMultipleChoice {
     // TODO: This Handler is called multiple times
     this.updateFormData.emit({ key, value });
   }
+
   componentDidLoad() {
     this.updateFormDataHandler(this.inputId, this.getValue());
   }