EQL: Handle case insensitivity for Comparisons

[rw-access]

Related to #56404

For EQL, == and != are always case-insensitive for the Python library and the Endpoint implementations. We should have the ability to make these case-insensitive.

The Python library will be updated to make <, <=, >=, > case-insensitive as well.
endgameinc/eql#30

[elasticmachine]

Pinging @elastic/es-ql (:Query Languages/EQL)

[astefan]

#53603 should help with this, I believe.

[costin]

Not needed anymore - see #62949