Clean up null-values test comments

Remove bug investigation comments from the null-values endpoint since
the issue is now resolved and the test is part of the E2E suite.

Author: sohankshirsagar

drift/instrumentation/psycopg/e2e-tests/src/app.py

@@ -733,10 +733,7 @@ def test_binary_format():
 
 @app.route("/test/null-values")
 def test_null_values():
-    """Test handling of NULL values in results.
-
-    BUG INVESTIGATION: NULL value serialization/deserialization may have issues.
-    """
+    """Test handling of NULL values in results."""
     try:
         with psycopg.connect(get_conn_string()) as conn, conn.cursor() as cur:
             # Create temp table with nullable columns

drift/instrumentation/psycopg/e2e-tests/src/test_requests.py

@@ -69,12 +69,7 @@
     make_request("GET", "/test/scalar-row-factory")
     make_request("GET", "/test/binary-format")
 
-    # =====================================================================
-    # PREVIOUSLY BUG-EXPOSING TEST ENDPOINTS
-    # See BUG_TRACKING.md for detailed analysis.
-    # =====================================================================
-
-    # Test 3: NULL values handling - FIXED (lazy capture mechanism)
+    # Test: NULL values handling (integrated into E2E suite)
     make_request("GET", "/test/null-values")
 
     # These still need investigation: