Avoid rebuilding buffered queries - #2

This pull request refactors the query execution logic in QueryResult to improve efficiency when dealing with buffered results, especially for nested collections. The main enhancement ensures that if a batch result is already available in the buffer, the query builder is not unnecessarily reconstructed. Additionally, a new test is added to verify this behavior.

Query execution optimization

• Refactored QueryResult::__construct to check for an existing batch result in the buffer before rebuilding the query builder, preventing redundant query construction and improving performance for nested collection queries. [1] [2]
• Updated the logic for retrieving the parent alias in nested queries to use an existing queryBuilder if available, or create a new one only when necessary.

Testing

• Added tests/QueryResultTest.php with a test case to confirm that when a buffered nested result exists, the query builder is not rebuilt, ensuring the optimization works as intended.