Handle not equal in custom keyword field

[bowenxia]

What changed?
When operation is "!=" for a custom keyword type, use "and" clause instead of "or" clause to connect the queries.

Why?
Context: the reason why we used 2 queries and connect those with "or" is that a custom keyword field can be either a value or an array (a list).

Thus when it comes with a "!=" operation, it was not returning correct result, because the query results included unnecessary parts.

How did you test it?
unit test
manual test in Pinot

Potential risks

Release notes

Documentation Changes

[neil-xie]

LGTM

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.76%. Comparing base (ebda4b1) to head (3db436e).

Additional details and impacted files

Files	Coverage Δ
common/pinot/pinotQueryValidator.go	86.87% <100.00%> (+0.14%)	⬆️

... 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 ebda4b1...3db436e. Read the comment docs.