Fix camera ambiguity warning in IOS example (bevyengine#6300)

# Objective

Fix a camera ambiguity warning in the IOS example

## Solution

I'm assuming that this was accidentally added when UI cameras stopped being a thing. So just delete the extra camera.

Author: rparrett

examples/ios/src/lib.rs

@@ -90,7 +90,6 @@ fn setup_scene(
     });
 
     // Test ui
-    commands.spawn(Camera2dBundle::default());
     commands
         .spawn(ButtonBundle {
             style: Style {