Enhanced snail entity with new features

Added a sprite to the Snail class and implemented animations for the snail's movements. The snail now has a body and shell texture, along with an eating shadow. Also, added logic to flip the sprite based on movement direction in the 'snail_eating' state. Furthermore, made CollisionShape2D invisible for better aesthetics.

resources/textures/snail_body.png.import

@@ -0,0 +1,34 @@
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