Remove quotes from SHOW CACHES query IDs

[ayymart]

SHOW PROXIED QUERIES returns e.g. q_xxxxxxxx but SHOW CACHES returns either `q_xxxxxxxx` or "q_xxxxxxxx" depending on the dialect. Metrics always represent query IDs unquoted. Grafana is ill equipped to deal with these kinds of discrepancies.

We should investigate whether its feasible to change this behavior.

_{From SyncLinear.com | REA-2798}