[releases/2.19] Fix lexical search required items string

[wanliAlex]

Change Summary

This pull request fixes a bug when generating lexical queries for required items.

For a lexical query '"required_1" "required_2"' with searchable attributes ['lexical_field_1', 'lexical_field_2'],
Previously, we have:

'marqo__lexical_lexical_field_1 contains "required_1" 
OR marqo__lexical_lexical_field_2 contains "required_1" 
AND marqo__lexical_lexical_field_1 contains "required_2" 
OR marqo__lexical_lexical_field_2 contains "required_2"'

Now we have:

'(marqo__lexical_lexical_field_1 contains "required_1" \
OR marqo__lexical_lexical_field_2 contains "required_1") \
AND (marqo__lexical_lexical_field_1 contains "required_2" \
OR marqo__lexical_lexical_field_1 contains "required_2")'

This fix applies to lexical search and hybrid search, for both structured index and semi-structured index.

Related Jira Ticket

Checklist

• Tests have been added for changes
• [n/a] Documentation has been updated
• [n/a] Breaking changes are clearly identified
• [n/a] Python client changes linked or N/A

For new field types:

• Tests cover score modifier usage of this new type
• Test indexes updated to cover the new type for all APIs (add docs, search, partial update, etc.)

[farshidz]

Please bump the version