Fix GraphicsGem template path in engine.json

Signed-off-by: Alex Peterson <[email protected]>

engine.json

@@ -123,7 +123,7 @@
         "Templates/DefaultGem",
         "Templates/DefaultProject",
         "Templates/GemRepo",
-        "Templates/GraphicsGems",
+        "Templates/GraphicsGem",
         "Templates/MinimalProject",
         "Templates/PrebuiltGem",
         "Templates/PythonToolGem",