fix: align unstructured-client version with pyproject.toml

unstructured-client>=0.44.0 requires pydantic>=2.12.5, but OGX uses
pydantic<2.12.0. Use >=0.25.0,<0.44.0 to avoid conflict.

Addresses review feedback from @cdoern

Author: sahana-sreeram

src/ogx/providers/registry/file_processors.py

@@ -197,7 +197,7 @@ def available_providers() -> list[ProviderSpec]:
             api=Api.file_processors,
             provider_type="remote::unstructured-api",
             adapter_type="unstructured-api",
-            pip_packages=["unstructured-client>=0.44.0"],
+            pip_packages=["unstructured-client>=0.25.0,<0.44.0"],
             module="ogx.providers.remote.file_processor.unstructured_api",
             config_class="ogx.providers.remote.file_processor.unstructured_api.UnstructuredApiFileProcessorConfig",
             api_dependencies=[Api.files],