bevy text problem example

Example for issue: bevyengine/bevy#16972

run

cargo run -p bevy_13

cargo run -p bevy_14

cargo run -p bevy_15

cargo run -p pullrequest_16991

cargo run -p bevy_main

control

space - change text display:

• Text2d with TextSpan
• Only Text2d
• Text2d with TextSpan with Visibility::Hidden
• despawn all text

mouse scroll - camera zoom