resolve_dependencies fails when multiple manifest files are present in a project

When running the resolve_dependencies pipeline on a project that contains multiple manifest files, the pipeline fails.

In our case, the project includes several requirements.txt files located in different subfolders.

The error seems to happen in the step that collects manifest inputs, probably in the get_manifest_inputs function, which appears to expect a single manifest file, not a list of files.
As a result, instead of resolving dependencies for all manifests found in the codebase, the pipeline stops with an exception.