Merge pull request #1251 from TechnologyEnhancedLearning/Develop/Fixes/TD-5500-My-Leraning-Page-OpenAPI-Issues-Fixes

TD-5500: Invalid date time in my learning page

Author: swapnamol-abraham

OpenAPI/LearningHub.Nhs.OpenApi.Services/Services/MyLearningService.cs

@@ -246,7 +246,7 @@ public async Task<List<MyLearningDetailedItemViewModel>> PopulateMyLearningDetai
                     MinorVersion = resourceActivity.MinorVersion,
                     Version = resourceActivity.MajorVersion + "." + resourceActivity.MinorVersion,
                     ResourceType = resourceActivity.Resource.ResourceTypeEnum,
-                    ActivityDate = resourceActivity.ActivityStart.GetValueOrDefault(),
+                    ActivityDate = resourceActivity.ActivityStart ?? resourceActivity.CreateDate,
                     ActivityStatus = (ActivityStatusEnum)resourceActivity.ActivityStatusId,
                     IsCurrentResourceVersion = resourceActivity.ResourceVersionId == resourceActivity.Resource.CurrentResourceVersionId,
                     VersionStatusId = (int?)resourceActivity.ResourceVersion.VersionStatusEnum,