sysui: configure 512 KB perfetto shmem buffer

Increase Perfetto's shmem buffer from default size (256 KB) to 512 KB
to avoid crashes or packet loss caused by shmem chunks exhaustion.

Bug: b/420587648
Flag: android.tracing.sysui_large_perfetto_shmem_buffer
Test: presubmit
Change-Id: I0eeb1737754d313d7a6a705ff8da81a6587d6af7