Make sure we require an encryption password if encryption is set to true for importing app backups

src/views/app.html

@@ -364,7 +364,7 @@
 
           <div class="form-group" ng-class="{ 'has-error': importBackup.error.password }">
             <label class="control-label" for="inputImportBackupPassword">{{ 'backups.configureBackupStorage.encryptionPassword' | tr }} <sup><a ng-href="https://docs.cloudron.io/backups/#encryption" class="help" target="_blank"><i class="fa fa-question-circle"></i></a></sup></label>
-            <input type="text" class="form-control" ng-model="importBackup.password" id="inputImportBackupPassword" ng-disabled="importBackup.busy" placeholder="Passphrase used to encrypt the backups">
+            <input type="text" class="form-control" ng-model="importBackup.password" id="inputImportBackupPassword" ng-disabled="importBackup.busy" ng-required="importBackup.encrypted" placeholder="Passphrase used to encrypt the backups">
           </div>
 
           <input class="ng-hide" type="submit" ng-disabled="importBackupForm.$invalid"/>

src/views/app.js

@@ -1249,6 +1249,7 @@ angular.module('Application').controller('AppController', ['$scope', '$location'
         backupId: '',
         password: '',
         mountOptions: {},
+        encrypted: false, // helps with ng-required when backupConfig is read from file
 
         clearForm: function () {
             // $scope.importBackup.provider = ''; // do not clear since we call this function on provider change