refactor: Conventionally reduce DiskSize to only 'int gb' for resize digital ocean volume

lib/logic/api_maps/rest_maps/server_providers/digital_ocean/digital_ocean_api.dart

@@ -456,7 +456,7 @@ class DigitalOceanApi extends RestApiMap {
 
   Future<GenericResult<bool>> resizeVolume(
     final String uuid,
-    final DiskSize size,
+    final int gb,
   ) async {
     bool success = false;
 
@@ -467,7 +467,7 @@ class DigitalOceanApi extends RestApiMap {
         '/volumes/$uuid/actions',
         data: {
           'type': 'resize',
-          'size_gigabytes': size.gibibyte.toInt(),
+          'size_gigabytes': gb,
           'region': region,
         },
       );

lib/logic/providers/server_providers/digital_ocean.dart

@@ -699,7 +699,7 @@ class DigitalOceanServerProvider extends ServerProvider {
   ) async =>
       _adapter.api().resizeVolume(
             volume.uuid!,
-            size,
+            size.gibibyte.toInt(),
           );
 
   @override