Add android user list data source to Perfetto probes

[annathedroid]

This update adds a new data source, android.user_list, to Perfetto. It parses the /data/system/users/user.list file, which is generated by UserManagerService, on system update or on user data change to record necessary Android User information directly into Perfetto traces.

The CL includes:

• Proto definitions for the data source config (UserListConfig) and trace packet (UserList).
• Implementation of the data source and parser logic in src/traced/probes/user_list/.
• Unit tests for the parsing logic.
• Build system updates (Android.bp, BUILD, .gn files) to incorporate the new source.
• Initially, the data source will include User ID (0 for SYSTEM, 10+ for others) and User Type (SYSTEM, FULL, GUEST, WORK/CLONE/PRIVATE PROFILE, RESTRICTED).

This change overcomes the current limitations in Perfetto traces, where only Android user ID (derived from process UID) is available, making it difficult to understand the impact of different user types on system performance. By adding a dedicated Multiuser data source, developers and performance analysts will be able to:

• Identify specific user types (system, headless system, secondary, restricted, guest, work profile, private profile, clone profile, communal profile) within Perfetto traces.
• Analyze in depth how different user types contribute to performance issues or unexpected behaviors (e.g., decreased battery drain with work profile running).

Bug: 391110239
Flag: android.multiuser.perfetto_multiuser_table
Test: tools/run_android_test out/default perfetto_unittests
Change-Id: I00d24cb92c11e5b2a5fbb0301787fa01ef3dd774