Fixed a memory leak in BLE (issue #4753) (#4761)

* Fixed crash on delete after disconnect

* Fixed memory leak when getting characteristics

* Removed guard

Co-authored-by: ushiboy <ushiboy.dev@gmail.com>

libraries/BLE/src/BLEClient.cpp

@@ -60,6 +60,7 @@ BLEClient::~BLEClient() {
 	   delete myPair.second;
 	}
 	m_servicesMap.clear();
+	m_servicesMapByInstID.clear();
 } // ~BLEClient