feat: Disable send kudos button when no receiver has been added - MEE…

…D-2418 - Meeds-io/meeds#54 (#328)

This change will disable the send kudos button when no receiver has been added.

kudos-webapps/src/main/webapp/vue-app/kudos/components/KudosApp.vue

@@ -304,7 +304,7 @@ export default {
       return this.numberOfKudosAllowed - this.remainingKudos;
     },
     sendButtonDisabled() {
-      return !this.kudosMessageText|| this.kudosMessageTextLength > this.MESSAGE_MAX_LENGTH || this.kudosMessageValidityLabel ;
+      return !this.kudosMessageText|| this.kudosMessageTextLength > this.MESSAGE_MAX_LENGTH || this.kudosMessageValidityLabel || !this.selectedReceiver;
     },
     remainingPeriodLabel() {
       return this.remainingDaysToReset === 1 ? this.$t('exoplatform.kudos.label.day') : this.$t('exoplatform.kudos.label.days') ;