Add interaction tests (#15251)

Content.IntegrationTests/Tests/Interaction/Click/InteractionSystemTests.cs

@@ -92,6 +92,7 @@ namespace Content.IntegrationTests.Tests.Interaction.Click
                 Assert.That(interactUsing);
             });
 
+            testInteractionSystem.ClearHandlers();
             await pairTracker.CleanReturnAsync();
         }
 
@@ -154,6 +155,7 @@ namespace Content.IntegrationTests.Tests.Interaction.Click
                 Assert.That(interactUsing, Is.False);
             });
 
+            testInteractionSystem.ClearHandlers();
             await pairTracker.CleanReturnAsync();
         }
 
@@ -214,6 +216,7 @@ namespace Content.IntegrationTests.Tests.Interaction.Click
                 Assert.That(interactUsing);
             });
 
+            testInteractionSystem.ClearHandlers();
             await pairTracker.CleanReturnAsync();
         }
 
@@ -275,6 +278,7 @@ namespace Content.IntegrationTests.Tests.Interaction.Click
                 Assert.That(interactUsing, Is.False);
             });
 
+            testInteractionSystem.ClearHandlers();
             await pairTracker.CleanReturnAsync();
         }
 
@@ -352,6 +356,7 @@ namespace Content.IntegrationTests.Tests.Interaction.Click
                 Assert.That(interactUsing, Is.True);
             });
 
+            testInteractionSystem.ClearHandlers();
             await pairTracker.CleanReturnAsync();
         }
 
@@ -367,6 +372,12 @@ namespace Content.IntegrationTests.Tests.Interaction.Click
                 SubscribeLocalEvent<InteractUsingEvent>((e) => InteractUsingEvent?.Invoke(e));
                 SubscribeLocalEvent<InteractHandEvent>((e) => InteractHandEvent?.Invoke(e));
             }
+
+            public void ClearHandlers()
+            {
+                InteractUsingEvent = null;
+                InteractHandEvent = null;
+            }
         }
 
     }