Improve experience/error message when having permissions issues

[miek]

Right now, if there's a permissions issue then an exception gets thrown from pyusb when trying to access string descriptors:

$>cynthion info
Cynthion version: 0.1.7
Apollo version: 1.1.0
Python version: 3.11.2 (main, May  2 2024, 11:59:08) [GCC 12.2.0]

Found Apollo stub interface!
Traceback (most recent call last):
  File "/home/cynthion/venv/bin/cynthion", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/home/cynthion/venv/lib/python3.11/site-packages/cynthion/commands/cli.py", line 92, in main
    args.func(args)
  File "/home/cynthion/venv/lib/python3.11/site-packages/cynthion/commands/cynthion_info.py", line 19, in cynthion_info
    if ApolloDebugger.print_info(force_offline=args.force_offline, out=logging.info,
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/cynthion/venv/lib/python3.11/site-packages/apollo_fpga/__init__.py", line 436, in print_info
    out(f"\tBitstream: {device.product} ({device.manufacturer})")
                        ^^^^^^^^^^^^^^
  File "/home/cynthion/venv/lib/python3.11/site-packages/usb/core.py", line 875, in product
    self._product = util.get_string(self, self.iProduct)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/cynthion/venv/lib/python3.11/site-packages/usb/util.py", line 313, in get_string
    raise ValueError("The device has no langid"
ValueError: The device has no langid (permission issue, no string descriptors supported or device error)

It hints at a permissions issue, but it's not great.

We should either do an earlier test of permissions or try and catch this exception, and print something more friendly.