Fix lazy load: remove broken RuntimeClient reconstruction in run()

The previous change referenced undefined names (lambda_runtime_api_addr,
use_thread_for_polling_next) inside run(), causing a NameError at init and
failing all runtime tests. run() already receives a fully constructed
lambda_runtime_client argument, so reconstruction is unnecessary and would
also clobber the LambdaMultiConcurrentRuntimeClient in the multi-concurrent
path. Removing those lines achieves the lazy-load goal (no module-level
LambdaRuntimeClient import) and fixes the black formatting failure.

Author: Mohammed Ehab

awslambdaric/bootstrap.py

@@ -503,8 +503,6 @@ def run(handler, lambda_runtime_client):
             _log_preview_runtime_warning()
 
             request_handler = _get_handler(handler)
-            from .lambda_runtime_client import LambdaRuntimeClient
-            lambda_runtime_client = LambdaRuntimeClient(lambda_runtime_api_addr, use_thread_for_polling_next)
         except FaultException as e:
             error_result = make_error(
                 e.msg,