MagTag Google Sheets URL redirect fails

There's an issue in
https://github.com/adafruit/Adafruit_Learning_System_Guides/blob/main/MagTag_Google_Sheets/weekly_planner/code.py
that's been transferred to Requests:
https://github.com/adafruit/Adafruit_CircuitPython_Requests/issues/103

I believe the issue is due to a required redirect to access the spreadsheet. This must have behaved differently in the past, but now the redirect is a `307` temporary redirect to a different host (subdomain.domain). Requests I believe only handles redirects within the same host.

While waiting for a Requests change, maybe there's an alternate way to serve the spreadsheet that won't encounter the issue, and gets the guide working again.

_Update: after more testing, turns out redirects to other domains are handled fine. The error arises from some other cause (unknown) - see the issue linked for more discussion._

Start with MagTag_Google_Sheets/weekly_planner/code.py and read the discussion in Adafruit_CircuitPython_Requests issue 103, since the reported redirect cause was later ruled out. Reproduce the spreadsheet request and compare its failure with the linked issue; done means the guide serves the spreadsheet successfully.

Written by the indexing model from the issue text.