Pinot handle customer keyword type empty val

[bowenxia]

What changed?

• Factor out create keyword query function
• Add a query to handle keyword query when value is empty

Why?

• Factor out create keyword query function:
  • to make code reuseable
• Add a query to handle keyword query when value is empty
  • this used to be an edge case that we forgot to handle. It caused errors in mono repo when custom queries a keyword field with empty value.
  • the customStringField query code was reused because querying an empty string basically means querying an empty keyword since when value is empty, it doesn't need partial match.

How did you test it?
unit test, manually test in Pinot

Potential risks

Release notes

Documentation Changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.23%. Comparing base (75079f7) to head (2f86179).
Report is 1 commits behind head on master.

Additional details and impacted files

Files with missing lines	Coverage Δ
common/pinot/pinotQueryValidator.go	87.82% <100.00%> (+0.12%)	⬆️

... and 6 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 75079f7...2f86179. Read the comment docs.

[davidporter-id-au]

nit consider using backticks to make things more readable when fighting quotes in quites

ie

`(JSON_MATCH(Attr, '"$.CustomKeywordField"!=''0''') and JSON_MATCH(Attr, '"$.CustomKeywordField[*]"!=''0'''))`

I guess, or similar, I'm having slight trouble following this because I've not spent enough time close to the Pinot component

[bowenxia]

Will do in the next PR. I enabled auto-merge for this one