test: parse JSON instead of asserting exact whitespace in response body test

Older httpx versions (lowest-direct CI matrix) serialize JSON with a space after
the colon; newer versions use compact separators. Parse the captured body instead
of asserting the exact string.

Author: maxisbey

tests/client/auth/test_bearer.py

@@ -2,6 +2,8 @@
 
 from __future__ import annotations
 
+import json
+
 import httpx
 import pytest
 
@@ -260,7 +262,7 @@ def handler(request: httpx.Request) -> httpx.Response:
             async with client.stream("POST", "https://api.example.com/mcp"):
                 pass  # pragma: no cover — auth flow raises before stream body opens
 
-    assert captured == ['{"error":"invalid_token"}']
+    assert [json.loads(body) for body in captured] == [{"error": "invalid_token"}]
 
 
 async def test_handler_receives_www_authenticate_header():