Allow users to set Latest Completed ToDos for all cars in new user setup

[baylessj]

Closes #194.

[DavBfr]

What is the goal of this? -- nevermind

I think the wizard few screens will eventually become more complicated than that. Maybe it's easier to configure the cars one by one.

[baylessj]

When my parents were first setting up their accounts, they added two cars in the first of the new user setup screens. The next setup screen asks for the last time that you changed the car's oil and tires, but it didn't specify which of the two cars that it was for, and only offered 1 car's worth of input fields. This allows the user to set the latest oil change and tire change mileages for all of the car's that they added in the first new user setup screen.

I removed you from the review for now because I realized that I forgot to check if the tests were working. Turns out, unsurprisingly, they aren't working. I'm going to grab dinner now but I'll get the tests passing later this evening and add you back to the review.

[codecov]

Codecov Report

Merging #261 into develop will increase coverage by 0.07%.
The diff coverage is 86.66%.

@@             Coverage Diff             @@
##           develop     #261      +/-   ##
===========================================
+ Coverage    88.58%   88.65%   +0.07%     
===========================================
  Files          130      130              
  Lines         5044     5085      +41     
===========================================
+ Hits          4468     4508      +40     
- Misses         576      577       +1

Impacted Files	Coverage Δ
.../welcome/views/new_user_setup/latestcompleted.dart	90.69% <86.66%> (+3.19%)	⬆️

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[baylessj]

Added you back to review the changes, unit tests are back to working now.

I agree that the onboarding will likely get more complicated in the future, and that it will make sense to set up cars one by one. That will be a pretty big reworking and would tie well into our idea of capping free tier users at one car, so maybe that could be a task for sometime soon? I can start putting together some Figma sketches or something to brainstorm the screenflow for that when the time comes.

[DavBfr]

With the next PR, we'll have to add units validation first: you don't want to manually convert your mileage to kilometers if you're in the US ;)

[DavBfr]

you don't need to repeat the variables from the StatefulWidget. You can get the values using widget.c