Fix DB call to only based min to last_changed_at

[macpie]

We used ton only check for last_changed_at in DB for some reason I changed it to more timestamps

Before:

oracles/mobile_config/src/gateway_info.rs

Line 384 in 19b2018

"SELECT entity_key, last_changed_at FROM mobile_radio_tracker WHERE last_changed_at >= $1";