We are trying to reduce the usage of the DataStore, as
it has caused the occasional headache in the past (see
for example ag/32804820).
This CL removes the storing download IDs on disk. Storing
the download IDs is unnecessary anyway, we schedule a new
download on a system_server or device reboot anyway.
Bug: 407940468
Test: atest NetworkSecurityUnitTests
Flag: com.android.net.ct.flags.certificate_transparency_service
Change-Id: I18bc752aa26978f877f669d343d5432f83a36ae4
0394ebba3b