[ES|QL] Improvements on appendWhereClauseToESQLQuery

[stratoula]

Describe the feature:

• Now that the ES team supports more casting naturally the ::string operator is not needed in the majority of the cases. We need to check where it is not needed and dont append it

• Improve the variables wrapping in backquotes, we can check if the name needs to be quoted and add them conditionally

[elasticmachine]

Pinging @elastic/kibana-esql (Team:ESQL)

[drewdaemon]

Now that the ES team supports more casting naturally the ::string operator is not needed in the majority of the cases. We need to check where it is not needed and dont append it

It's true that they do some implicit casting, but there may be inconsistencies (I have discovered them in the past). I guess we should think about which is the priority: help the ES team be more consistent or make sure the queries are always correct.

If we want to help the ES team be consistent, we could remove the explicit string casting, but there may be bugs that need to be reported and fixed.

I kind of like that route since it makes everyone better, but I'm just pointing out a potential cost.

[stratoula]

Yes this why it is a priority low Drew now, I agree with you ;)