Use buffer size for NativeAllocationRegistry instead of a fixed value

When calling NativeAllocationRegistry for HardwareBuffer, it needs the
correct size so GC knows how much memory has been allocated and when to
run. The current behavior uses a fixed size so it's likely the buffer is
actually consuming more memory than what GC thinks.

Test: atest ContentCapturePerfTests:LoginTest
Bug: 168149157
Bug: 168154840
Change-Id: Ife174478b2b76214b438de2757289a973330c979