[examples] Fix memory out of bounds in [shapes] example - ball physics

[Jopestpe]

Description

• Fixes memory out of bounds in [shapes] example - ball physics by using malloc/free

Changelog

• Modified examples/shapes/shapes_ball_physics.c - code
• Updated examples/shapes/shapes_bouncing_ball.png – refreshed screenshot for accuracy

[raysan5]

@Jopestpe Thanks for the review but... did you try it on PLATFORM_WEB?

Because this change is probably not related to the listed issue...

[Jopestpe]

@Jopestpe Thanks for the review but... did you try it on PLATFORM_WEB?

Because this change is probably not related to the listed issue...

My bad, I didn't mention it earlier, I tested it on both Linux and the web. Initially, reducing MAX_BALLS to 1300 or less didn't cause the memory out of bounds since as it fits within Emscripten's STACK_SIZE (64*1024), but I preferred to move it to the heap while keeping the 5000 from the original script.