MSSQL

...G...... [ZBX-27289] fixed problem with failed connection creation causing panic in Zabbix agent 2 mssql plugin

* commit '36f752926f56f2822cd52bcb56b65956d775f56b':
  ...G...... [ZBX-27289] update sql for integration tests
  ...G...... [ZBX-27289] added changelog
  ...G...... [ZBX-27289] style improvements
  ...G...... [ZBX-27289] fixed problem with singleflight connection creation failing with panic on connection creation failing