Smartquery: Fix querying PostgreSQL with Grafana 11

[amotl]

About

@hbaghar reported that querying PostgreSQL would no longer work.

• Upgrading grafana to 11.0.0 breaks smartquery subsystem #180

This patch attempts to fix it, but it has not been tested.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.33%. Comparing base (8756601) to head (f537f15).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #208   +/-   ##
=======================================
  Coverage   92.33%   92.33%           
=======================================
  Files          27       27           
  Lines        1814     1814           
=======================================
  Hits         1675     1675           
  Misses        139      139           

Flag	Coverage Δ
unittests	92.33% <100.00%> (ø)

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