VulkanStagingBuffers stat continually to grows.

On Android phones, VulkanStagingBuffers continually grows when the scene is static.

From looking at FStagingManager, it appears the VulkanStagingBuffers atat is only updated on buffer acquisition, but not on release.

Reproducibility Steps

1. Package the 3D scene and publish it to a real device.

2. Launch the game and leave it idle in the scene. Memory usage will slowly increase.

3. Observe the VulkanStagingBuffers item through LLM and see it continue to increase.