Measurement selection does not consider all measurement tables for not-equal operators

[Piiit]

For example: mvalue.neq.1 would choose only measurement_double as table, because 1 is a number, but the not-equal operator should also include string and json measurements instead.

[sseppi]

@clezag I've seen you self assigned this issue, are you working on it? Shall we keep it open?

[clezag]

@sseppi Let's keep it open