Implement two performance improvements for Lookup Join on Expression

1. Do not send duplicate columns more than once to the lookup node. Example column left_id will be just sent once instead of 3 times, even though it is used 3 times in the expression
2. Use the termsQueryList that we build for field based join for Expression Based Joins too, if it uses equals operator. This allows us to take advantage of the optimizations made for field based join and apply them for expression based join whenever possible. We end up doing less work per row, so we expect this to be faster.

Covered by existing UTs lookup-join-expression.LookupJoinOnSameLeftFieldTwice and multiple UTs on equals.

Benchmarks show only moderate improvement 50sec to 43sec (14% improvement) in esql_lookup_join_expression_eq_100k_keys_where_few_matching_like_limit_10000. See #135036 (comment)