Fix ConjureHTTPError pickling crash in multiprocessing

[matthewbayer]

Before this PR

PR #167 fixed a copy.copy() crash on ConjureHTTPError by adding a __copy__ override, but the same underlying issue also affects pickling. BaseException.__reduce__ produces pickle instructions that call ConjureHTTPError.__init__(message_string), passing the string message as the http_error argument. Since __init__ expects an HTTPError object with a .response attribute, this crashes with AttributeError: 'str' object has no attribute 'response'.

This surfaces when a ConjureHTTPError is raised inside a ProcessPoolExecutor worker — the pool tries to pickle the exception to send it back to the parent process, the unpickle fails, and the worker crashes with BrokenProcessPool.

After this PR

ConjureHTTPError can be safely pickled and unpickled. This unblocks use of ProcessPoolExecutor (and any other pickle-based serialization) with code that may raise ConjureHTTPError.

==COMMIT_MSG==
Fix ConjureHTTPError pickling crash in multiprocessing

Override __reduce__ to bypass __init__ on reconstruction, matching the existing __copy__ fix from #167.
==COMMIT_MSG==

Possible downsides?

None. The current behavior (crashing on pickle) is a bug, not a contract. The public API, class hierarchy, and constructor signature are unchanged.

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Description

Fix ConjureHTTPError pickling crash in multiprocessing

Override __reduce__ to bypass __init__ on reconstruction, matching the existing __copy__ fix from #167.

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🐛 Fixes

• Fix ConjureHTTPError pickling crash in multiprocessing

  Override __reduce__ to bypass __init__ on reconstruction, matching the existing __copy__ fix from fix: shallow copy issue of ConjureHTTPError #167. (#178)