Dashboard uses legacy PCA filename

[lukekoch]

Describe the bug
Dashboard attempts to fetch from pca loadings rather than constribution of variables.

To Reproduce
Steps to reproduce the behavior:
Add and load a dataset from a recent version of taXaminer

Stacktraces

Traceback (most recent call last):
  File "/home/luke/.local/lib/python3.8/site-packages/flask/app.py", line 2548, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/luke/.local/lib/python3.8/site-packages/flask/app.py", line 2528, in wsgi_app
    response = self.handle_exception(e)
  File "/home/luke/.local/lib/python3.8/site-packages/flask_cors/extension.py", line 165, in wrapped_function
    return cors_after_request(app.make_response(f(*args, **kwargs)))
  File "/home/luke/.local/lib/python3.8/site-packages/flask/app.py", line 2525, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/luke/.local/lib/python3.8/site-packages/flask/app.py", line 1822, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/luke/.local/lib/python3.8/site-packages/flask_cors/extension.py", line 165, in wrapped_function
    return cors_after_request(app.make_response(f(*args, **kwargs)))
  File "/home/luke/.local/lib/python3.8/site-packages/flask/app.py", line 1820, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/luke/.local/lib/python3.8/site-packages/flask/app.py", line 1796, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "/home/luke/.local/lib/python3.8/site-packages/flask_cors/decorator.py", line 128, in wrapped_function
    resp = make_response(f(*args, **kwargs))
  File "/home/luke/projects/taxaminer-dashboard/api/main.py", line 303, in pca_contributions
    data = file_io.load_pca_coords(my_dir)
  File "/home/luke/projects/taxaminer-dashboard/api/file_io.py", line 174, in load_pca_coords
    with open(f"./datasets/{base_path}/pca_loadings.csv", 'r') as file:
FileNotFoundError: [Errno 2] No such file or directory: