Add null operator in ModuleState.ModuleDefinition

[hishamco]

No description provided.

[sbwalker]

@hishamco this is a valid issue. I am guessing you were able to trigger this issue is by deleting a module assembly from the /bin for a module which is already in use within a site - which essentially creates an "orphaned module" scenario (hence the ModuleDefinition property is null).

In regards to fixing the problem, my preference would be to move the _module assignment to within the condition if block where all of other assignments which depend on ModuleDefinition are already located. It makes the logic clearer.

if (ModuleState.ModuleDefinition != null)
{
>>   _module = ModuleState.ModuleDefinition.Name; <<
   _permissionNames = ModuleState.ModuleDefinition?.PermissionNames;

if you make this change I will merge this PR.