Swap gizmo storage and buffer to keep the allocation

[IceSentry]

Objective

• When drawing gizmos from multiple systems, combining the buffers at the end of the frame can trigger a lot of new allocations

Solution

• Instead of taking the buffer and creating a new one, swap with the existing buffer and clear the one that stays in the main world. This way the allocation is reused.
• Technically, if someone spawns a lot of gizmos for a single frame then never spawns them again then the memory will never be cleared but I believe this isn't a common use case for gizmos but this is a tradeoff. If it becomes an issue we could check how the capacity vs len compares over a few frame and shrink it.

Testing

• I added a new benchmark that measures the impact of this over multiple lines drawn and systems.
• If you have a single system drawing a few lines then this new approach is marginally slower but in every other case it's faster.

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