Reconcile the concept of Edict & Networkable across the codebase (#1903)

* Reconcile the concept of Edict & Networkable across the codebase

* There's no need to check this, it's done elsewhere. Also could be null (segfault)

* This was never needed

* Pseudo review changes

Re-added removed null checks, and added new ones.

Changed the error messages in Get/SetProp natives to better reflect reality.

* Don't change the behaviour of GetEntityNetClass

* Overload IGameHelpers::FindServerClass

* Make error messages more accurate

* Fix a dev comment

* Rename FindServerClass

---------

Co-authored-by: Kenzzer <[email protected]>

public/IGameHelpers.h

@@ -40,7 +40,7 @@
  */
 
 #define SMINTERFACE_GAMEHELPERS_NAME		"IGameHelpers"
-#define SMINTERFACE_GAMEHELPERS_VERSION		11
+#define SMINTERFACE_GAMEHELPERS_VERSION		12
 
 class CBaseEntity;
 class CBaseHandle;
@@ -351,6 +351,13 @@ namespace SourceMod
 		 * @return				64-bit server Steam id.
 		 */
 		virtual uint64_t GetServerSteamId64() const =0;
+
+		/**
+		 * @brief Finds a given entity's server class.
+		 *
+		 * @return				ServerClass pointer on success, nullptr on failure.
+		 */
+		virtual ServerClass *FindEntityServerClass(CBaseEntity *pEntity) = 0;
 	};
 }