Remove the note about GLES2 exclusive 2D batching (#5051)

Unified GLES3 / GLES2 was merged in 3.2.4 beta (3.3 stable)

https://github.com/godotengine/godot/pull/42119

tutorials/optimization/batching.rst

@@ -16,10 +16,6 @@ of work for the user in the GPU driver at the cost of more expensive draw calls.
 As a result, applications can often be sped up by reducing the number of draw
 calls.
 
-.. note::
-
-    2D batching is currently only supported when using the GLES2 renderer.
-
 Draw calls
 ^^^^^^^^^^