Steps to reproduce:

1. Send history.push without clock and ns a few times in one second.

Result:
Zabbix Server tries to insert row with ns=0.

3259167:20240626:161246.524 [Z3008] query failed due to primary key constraint: [0] PGRES_FATAL_ERROR:ERROR:  duplicate key value violates unique constraint "21645_11430_history_str_pkey"
DETAIL:  Key (itemid, clock, ns)=(2531417, 1719407565, 0) already exists. 

It leads to 100% utilization of history syncer internal processes and false alerts, because of nodata.
Expected:
If clock or ns are not present, history.push must populate them with current timestamp.
Or clock and ns must be required.