[1.7] Able to pick up items with a full inventory in Creative mode

Verification builds:
1.7.0.2 Release 1117901

Summary:
When the player is in creative mode with a full inventory they are still able to pick up items. These items however do not appear in the inventory and thus are lost/removed from the game.

Impact:
This could affect player's experience in content on the store, and in the base game, especially if the item lost is a key item in the game and could break content.

Repro Steps:

1. Create a world with cheats enabled and default gamemode in Creative mode
2.  Fill your inventory with items 
3. Drop an item on the group 
4. Observe the item be picked up, indicated by the sound, but does not appear in the inventory
5. Drop another item on the ground and change your gamemode to survival to observer the item not be pick up

Observed Results: 
Items are deleted from the game when in creative and with a full inventory 

Expected Results: 
The item is not able to be picked up when in creative mode with a full inventory 

Screenshots/Videos attached: 
No