[ICU-15403] Trim whitespace on storage buckets and host sets json attrs serializers (#2636)

* trim whitespace on json attrs in storage bucket serializer

* add test for storage bucket serializer

* move trimWhitespace check to application level

* add trimWhitespace to preferred_endpoints attr

* add conditional for string arr

* trim whitespace on str arr

* add check for null val

* refactor, move logic

* relocate comment

* add unit test for application serializer

addons/api/addon/generated/models/host-set.js

@@ -88,6 +88,7 @@ export default class GeneratedHostSetModel extends BaseModel {
       name: ['aws', 'azure', 'gcp'],
     },
     emptyArrayIfMissing: true,
+    trimWhitespace: true,
   })
   preferred_endpoints;
 

addons/api/addon/generated/models/storage-bucket.js

@@ -70,6 +70,7 @@ export default class GeneratedStorageBucketModel extends BaseModel {
   @attr('string', {
     isNestedAttribute: true,
     description: 'The AWS region to use.',
+    trimWhitespace: true,
   })
   region;
 
@@ -109,6 +110,7 @@ export default class GeneratedStorageBucketModel extends BaseModel {
   @attr('string', {
     isNestedAttribute: true,
     description: 'The role ARN to use.',
+    trimWhitespace: true,
   })
   role_arn;