fix: handle null django_id in identity overrides (#122)

Author: rolodato

Flagsmith.Client.Test/Fixtures.cs

@@ -84,6 +84,7 @@ internal class Fixtures
           'featurestate_uuid': '1bddb9a5-7e59-42c6-9be9-625fa369749f',
           'feature_state_value': 'some-overridden-value',
           'enabled': false,
+          'django_id': null,
           'environment': 1,
           'identity': null,
           'feature_segment': null

Flagsmith.Engine/Feature/Models/FeatureStateModel.cs

@@ -22,7 +22,7 @@ public class FeatureStateModel
         [JsonProperty(PropertyName = "multivariate_feature_state_values")]
         public List<MultivariateFeatureStateValueModel> MultivariateFeatureStateValues { get; set; }
         [JsonProperty(PropertyName = "django_id")]
-        public int DjangoId { get; set; }
+        public int? DjangoId { get; set; }
         public string FeatureStateUUID { get; set; } = new Guid().ToString();
         [JsonProperty(PropertyName = "feature_segment")]
         public FeatureSegmentModel FeatureSegment { get; set; } = null;
@@ -33,7 +33,7 @@ public object GetMultivariateValue(string identityId)
         {
             var percentageValue = Hashing.GetHashedPercentageForObjectIds(new List<string>
             {
-              DjangoId != 0 ? DjangoId.ToString() : FeatureStateUUID,
+              DjangoId != null ? DjangoId.ToString() : FeatureStateUUID,
               identityId.ToString()
             });
             var startPercentage = 0.0;

Flagsmith.FlagsmithClient/Flagsmith.FlagsmithClient.csproj

@@ -7,7 +7,7 @@
     <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
     <PackageId>Flagsmith</PackageId>
     <Title>Flagsmith</Title>
-    <Version>5.4.2</Version>
+    <Version>5.4.3</Version>
     <Authors>flagsmith</Authors>
     <Company>Flagsmith</Company>
     <PackageDescription>Client SDK for Flagsmith. Ship features with confidence using feature flags and remote config. Host yourself or use our hosted version at https://flagsmith.com/</PackageDescription>