Fix InvalidCastException on manual workflow restart

When restart workflow that starts from any ContentActivity manually InvalidCastException writes to log. It happens because input object deserializes from JSON and contains Dictionary instead of expected ContentEventContext  object.

src/OrchardCore.Modules/OrchardCore.Contents/Workflows/Activities/ContentActivity.cs

@@ -1,3 +1,4 @@
+using System.Collections;
 using System.Text.Json;
 using System.Text.Json.Nodes;
 using Microsoft.Extensions.Localization;
@@ -53,11 +54,14 @@ public override IEnumerable<Outcome> GetPossibleOutcomes(WorkflowExecutionContex
 
     public override Task OnInputReceivedAsync(WorkflowExecutionContext workflowContext, IDictionary<string, object> input)
     {
-        var contentEvent = input?.GetValue<ContentEventContext>(ContentEventConstants.ContentEventInputKey);
-
-        if (contentEvent != null)
+        if(input != null && input.TryGetValue(ContentEventConstants.ContentEventInputKey, out var contentEventObj))
         {
-            InlineEvent = contentEvent;
+            InlineEvent = contentEventObj switch
+            {
+                ContentEventContext contentEvent => contentEvent,
+                IDictionary<string, object> contentEventDict => JObject.FromObject(contentEventDict).ToObject<ContentEventContext>(),
+                _ => throw new InvalidCastException($"Cannot convert {contentEventObj} to ContentEventContext")
+            };
 
             InlineEvent.IsStart = workflowContext.Status == WorkflowStatus.Starting;
         }