feat: more shopping list enhancements

[michael-genson]

What type of PR is this?

(REQUIRED)

• bug
• feature

What this PR does / why we need it:

(REQUIRED)

A bunch of enhancements to the shopping list:

• fixed some visual bugs
• fixed random list item re-ordering nonsense and made it consistent

And I added a task that purges old, checked-off shopping list items over a threshold (currently set to 100). I have a feeling a lot of users don't know how big their "checked-off" list gets, which eventually bogs down the shopping list.

Which issue(s) this PR fixes:

(REQUIRED)

N/A

Testing

(fill-in or delete this section)

Pytest for the new task

Release Notes

(REQUIRED)

fixed some visual shopping list bugs
fixed shopping list items re-arranging themselves in certain instances
automatically delete older checked-off shopping list items when there are more than 100 of them

[michael-genson]

I think I did the reduce right? Pretty sure it works