Remove bytes after first zero length field in legacy advertisements

This is for compatibility with many existing old devices, that have
non-zero bytes after zero length field. This is currently causing
advertisements to be dropped, rendering those devices invisible.

Bug: 68907583
Test: AdvertiseDataParserTest.RemoveTrailingZerosMalformed
Change-Id: Ib51950f7e0c6a2771f56c6f69108fa10f2517f38