Handle empty statement in psycopg instrumentation

Fixes #2643

Author: Holi0317

instrumentation/opentelemetry-instrumentation-psycopg/src/opentelemetry/instrumentation/psycopg/__init__.py

@@ -269,7 +269,8 @@ def get_operation_name(self, cursor, args):
         if isinstance(statement, Composed):
             statement = statement.as_string(cursor)
 
-        if isinstance(statement, str):
+        # `statement` can be empty string. See #2643
+        if isinstance(statement, str) and statement != "":
             # Strip leading comments so we get the operation name.
             return self._leading_comment_remover.sub("", statement).split()[0]