Fix 3D sphere example always saying wireframe is False

[pushfoo]

Follow-up to issues discovered during #1731

Changes

• Make the wireframe label update from window.wireframe instead of window.ctx.wireframe, which is always left as False by on_draw's text drawing
• Only update the relevant label during a keypress instead of updating all of them
• Fix initial capitalization for cull face's label

How to test

python -m arcade.examples.gl.3d_sphere

[einarf]

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