Remove file extension checking

When saving pipeline definition, file_path of steps could be
any file path within the allowed directories. It's not necessary
to reject the request if the file path is not allowed
file extension This allows users to save the path per keystroke.

services/orchest-webserver/app/app/views/views.py

@@ -861,13 +861,6 @@ def pipelines_json(project_uuid, pipeline_uuid):
                         "File is neither in the project, nor in the data directory."
                     )
 
-                extensions = list(
-                    map(lambda x: f".{x.lower()}", ["ipynb", "py", "R", "sh", "jl"])
-                )
-
-                if not step["file_path"].endswith(tuple(extensions)):
-                    raise ValueError("Unsupported pipeline step file type.")
-
                 if not step["file_path"].startswith("/"):
                     step["file_path"] = normalize_project_relative_path(
                         step["file_path"]