Remove validity time constraint in DNS query log

Carriers will use DNS query logs in tests. Removes log expiration time
limit so logs persist long enough for 24 hour testing.

Bug: 279596912
Bug: 231264474
Bug: 200748696
Test: atest resolv_unit_test:DnsQueryLogTest
Change-Id: Ib98b16053d0386e98be370fa6138d667dfcb03c9