Add subpass dependencies to examples

[YouSafe]

This PR aims to fix some of the sync validation errors.

Adding those subpass dependencies fixes all sync issues for the example example but NOT for user_texture.

Fixing user_texture takes a bit more work, as the current swapchain image is used for both shader read and color attachment at the same time. A potential fix would be to render the scene onto a separate image.

Also, the // Clear framebuffer section is not needed because begin_render_pass already clears the framebuffer image.