FormLocation ArgumentNullException

[jtkech]

When saving the settings of an HttpRequestEvent activity, if the new Form Location property is left blank, which is a valid use case, the following ArgumentNullException is logged.

System.ArgumentNullException: Value cannot be null. (Parameter 'o')
at Newtonsoft.Json.Utilities.ValidationUtils.ArgumentNotNull(Object value, String parameterName)
at Newtonsoft.Json.Linq.JToken.FromObjectInternal(Object o, JsonSerializer jsonSerializer)
at Newtonsoft.Json.Linq.JToken.FromObject(Object o)
at OrchardCore.Workflows.Activities.Activity.SetProperty(Object value, String name)
in C:\...\src\OrchardCore\OrchardCore.Workflows.Abstractions\Activities\Activity.cs:line 153