fix: restore 'Discovered' log message for E2E test compatibility

The refactoring changed the log message from 'Discovered' to 'Instrumented',
breaking the E2E test regex in end_to_end_test_utilities.py:225.

Co-authored-by: Kevin Turcios <KRRT7@users.noreply.github.com>

Author: github-actions[bot]

codeflash/optimization/function_optimizer.py

@@ -1698,7 +1698,7 @@ def get_instrumented_path(original_path: str, suffix: str) -> Path:
 
         if existing_test_files_count > 0 or replay_test_files_count > 0 or concolic_coverage_test_files_count > 0:
             logger.info(
-                f"Instrumented {existing_test_files_count} existing unit test file"
+                f"Discovered {existing_test_files_count} existing unit test file"
                 f"{'s' if existing_test_files_count != 1 else ''}, {replay_test_files_count} replay test file"
                 f"{'s' if replay_test_files_count != 1 else ''}, and "
                 f"{concolic_coverage_test_files_count} concolic coverage test file"