PROE-2074: Fix broken ps-fuzz dependency causing crashes due to non-pinned httpx library version

httpx library broke its interface over time and it was not pinned in setup.py deps list. Fix is to pin it to compatible version.

Original crash was:
  File "/Users/vitaly/work/oss-contributions/ps-fuzz/venv/bin/prompt-security-fuzzer", line 8, in <module>
    sys.exit(main())
  File "/Users/vitaly/work/oss-contributions/ps-fuzz/ps_fuzz/cli.py", line 65, in main
    interactive_shell(app_config)
  File "/Users/vitaly/work/oss-contributions/ps-fuzz/ps_fuzz/interactive_mode.py", line 153, in interactive_shell
    stage = stage.show(state)
  File "/Users/vitaly/work/oss-contributions/ps-fuzz/ps_fuzz/interactive_mode.py", line 69, in show
    if func: func(state)
  File "/Users/vitaly/work/oss-contributions/ps-fuzz/ps_fuzz/prompt_injection_fuzzer.py", line 177, in run_fuzzer
    target_client = ClientLangChain(app_config.target_provider, model=app_config.target_model, temperature=0)
  File "/Users/vitaly/work/oss-contributions/ps-fuzz/ps_fuzz/chat_clients.py", line 38, in __init__
    self.client = chat_models_info[backend].model_cls(**kwargs)
  File "/Users/vitaly/work/oss-contributions/ps-fuzz/venv/lib/python3.13/site-packages/langchain_core/load/serializable.py", line 107, in __init__
    super().__init__(**kwargs)
  File "/Users/vitaly/work/oss-contributions/ps-fuzz/venv/lib/python3.13/site-packages/pydantic/v1/main.py", line 352, in __init__
    raise validation_error
pydantic.v1.error_wrappers.ValidationError: 1 validation error for ChatOpenAI
__root__
  Client.__init__() got an unexpected keyword argument 'proxies' (type=type_error)

Author: vitaly-ps

setup.py

@@ -31,6 +31,7 @@
     ],
     python_requires='>=3.7',
     install_requires=[
+        "httpx>=0.24.0,<0.25.0",
         "openai==1.6.1",
         "langchain==0.0.353",
         "langchain-community==0.0.7",