Fix Service object leak on emulation stop

Services created with the ServiceFramework base class install themselves as HleHandlers with an owning shared_ptr in the ServerPort ServiceFrameworkBase::port member variable, creating a cyclic ownership between ServiceFrameworkBase and the ServerPort, preventing deletion of the service objects.

Fix that by removing the ServiceFrameworkBase::port member because that was only used to detect multiple attempts at installing a port. Instead store a flag if the port was already installed to achieve the same functionality.

src/core/hle/service/service.h

@@ -96,11 +96,9 @@ private:
     /// Maximum number of concurrent sessions that this service can handle.
     u32 max_sessions;
 
-    /**
-     * Port where incoming connections will be received. Only created when InstallAsService() or
-     * InstallAsNamedPort() are called.
-     */
-    Kernel::SharedPtr<Kernel::ServerPort> port;
+    /// Flag to store if a port was already create/installed to detect multiple install attempts,
+    /// which is not supported.
+    bool port_installed = false;
 
     /// Function used to safely up-cast pointers to the derived class before invoking a handler.
     InvokerFn* handler_invoker;