[v4.4] initiate_emrc_false.js needs to wait for the initial checkpoint

initiate_emrc_false.js added in SERVER-58780 tests that a secondary with eMRC=false that previously fails replSetInitiate doesn't have to go through initial sync again on restart. The test relies on the secondary node to have an initial checkpoint (i.e. an non-null WiredTiger recoveryTimestamp) before the restart. So we should explicitly wait for it.