Added option to disable edit button in asset widgets when there are no asset selected. (#7521)

Added new attribute "DisableEditButtonWheNoAssetSelected" to PropertyAssetCtrl. By default it's false, keeping the original behavior of leaving the edit button enabled and if it's clicked while there is no asset assigned it'll try to create a new one.

PhysX mesh asset property uses now this new feature.

Signed-off-by: moraaar moraaar@amazon.com

Gems/PhysX/Code/Source/EditorColliderComponent.cpp

@@ -60,6 +60,7 @@ namespace PhysX
                         "Specifies the PhysX mesh collider asset for this PhysX collider component.")
                         ->Attribute(AZ_CRC_CE("EditButton"), "")
                         ->Attribute(AZ_CRC_CE("EditDescription"), "Open in Scene Settings")
+                        ->Attribute(AZ_CRC_CE("DisableEditButtonWhenNoAssetSelected"), true)
                     ->DataElement(AZ::Edit::UIHandlers::Default, &EditorProxyAssetShapeConfig::m_configuration, "Configuration",
                         "PhysX mesh asset collider configuration.")
                         ->Attribute(AZ::Edit::Attributes::Visibility, AZ::Edit::PropertyVisibility::ShowChildrenOnly);