Define the metric definition for GrAlloc allocation per process metric.

Add a new metric to track the per-process GrAlloc allocs Perfetto Counter
Track which tracks the per process graphic buffer allocations/deallocations.

Bug: 442355906
Test: atest SysUiMetricsV2Test
Flag: EXEMPT added new perfetto metric for sysui
Change-Id: Ia91214ee0ed844fe4bb0810bcfe92a0a5292a569