fix(cli): Fix crash in templateflow get when matching one file

[effigies]

Currently:

❯ uvx templateflow get MNI152NLin6Asym --res 2 --desc LR -s T1w
Traceback (most recent call last):
  File "/home/chris/.cache/uv/archive-v0/N20Na8Y61YObB3kT5W_Jk/bin/templateflow", line 10, in <module>
    sys.exit(main())
             ~~~~^^
  File "/home/chris/.cache/uv/archive-v0/N20Na8Y61YObB3kT5W_Jk/lib/python3.13/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/home/chris/.cache/uv/archive-v0/N20Na8Y61YObB3kT5W_Jk/lib/python3.13/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
  File "/home/chris/.cache/uv/archive-v0/N20Na8Y61YObB3kT5W_Jk/lib/python3.13/site-packages/click/core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/home/chris/.cache/uv/archive-v0/N20Na8Y61YObB3kT5W_Jk/lib/python3.13/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/chris/.cache/uv/archive-v0/N20Na8Y61YObB3kT5W_Jk/lib/python3.13/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
  File "/home/chris/.cache/uv/archive-v0/N20Na8Y61YObB3kT5W_Jk/lib/python3.13/site-packages/templateflow/cli.py", line 144, in get
    click.echo('\n'.join(f'{match}' for match in api.get(template, **entities)))
                                                 ~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
TypeError: 'PosixPath' object is not iterable