chore(agentic-ci): declare httpx dependency in data-designer-config (#836)

data_designer.config imports httpx via the lazy import system
(`lazy.httpx.AsyncClient()` in config/utils/media_helpers.py) but the
package does not declare it. A standalone install of data-designer-config
would fail with ModuleNotFoundError on the async media-download path.

Add `httpx>=0.27.2,<1`, copying the specifier already used by the sibling
data-designer-engine package.

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Author: github-actions[bot]

packages/data-designer-config/pyproject.toml

@@ -20,6 +20,7 @@ classifiers = [
 ]
 
 dependencies = [
+    "httpx>=0.27.2,<1",
     "jinja2>=3.1.6,<4",
     "numpy>=1.23.5,<3",
     "pandas>=2.3.3,<3",