fix: AutocompleteWidget: Scrollbar + dividers + correct width

[g123k]

On product edition pages, when there are fields with suggestions, the list can be improved by:

• Adding some dividers
• Adding a scrollbar
• Ensuring the content fits the screen width

Previous UI:

New UI:

Will fix #2703

[g123k]

Note: Despite my PR, we should also add that clicking outside the list should close it

[codecov-commenter]

Codecov Report

Merging #2704 (e445a30) into develop (2ea0da3) will decrease coverage by 1.66%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           develop   #2704      +/-   ##
==========================================
- Coverage     8.86%   7.19%   -1.67%     
==========================================
  Files          161     219      +58     
  Lines         6623   10605    +3982     
==========================================
+ Hits           587     763     +176     
- Misses        6036    9842    +3806     

Impacted Files	Coverage Δ
...kages/smooth_app/lib/widgets/attribute_button.dart	0.00% <0.00%> (-92.00%)	⬇️
...s/smooth_app/lib/data_models/user_preferences.dart	8.73% <0.00%> (-23.57%)	⬇️
packages/smooth_app/lib/themes/smooth_theme.dart	60.00% <0.00%> (-22.98%)	⬇️
...p/lib/generic_lib/dialogs/smooth_alert_dialog.dart	15.11% <0.00%> (-19.10%)	⬇️
...mooth_app/lib/data_models/product_preferences.dart	21.68% <0.00%> (-9.75%)	⬇️
packages/smooth_app/lib/main.dart	14.65% <0.00%> (-3.24%)	⬇️
.../smooth_app/lib/pages/onboarding/welcome_page.dart	0.00% <0.00%> (-3.13%)	⬇️
.../smooth_app/lib/pages/onboarding/scan_example.dart	0.00% <0.00%> (-2.28%)	⬇️
...p/lib/pages/onboarding/consent_analytics_page.dart	0.00% <0.00%> (-1.57%)	⬇️
...ackages/smooth_app/lib/pages/scan/scan_header.dart	3.33% <0.00%> (-1.43%)	⬇️
... and 236 more

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[monsieurtanuki]

Note: Despite my PR, we should also add that clicking outside the list should close it

In a perfect world the list should probably take as much space as possible, therefore the notion of "outside the list" is not easy.
Similar suggestion: the text field "clear" button should clear the field AND collapse the list. (not sure if an empty text field triggers the auto complete or if we wait for at least 1 input character).

[VaiTon]

I find reading this a bit difficult. What about moving part of it to a fun?

[monsieurtanuki]

I find reading this a bit difficult. What about moving part of it to a fun?

@VaiTon In flutter we call that Widgets ;)
That said, I must say that code is not fun to read as there are almost no changes and the only difference is that the LayoutBuilder shifts the whole code. As we use flutter and automatic format there's not much we can do about it.
Perhaps this time move that Row into an ad-hoc Widget: that won't solve @VaiTon's problem now but at least next time any change would be easier to review. No a strong requirement from my side, though.

[g123k]

I have split the child of the AutocompleteList to a dedicated Widget.
However for the simple_input_widget file, there is too much work to do, and is thus outside the goal of this PR.

Please open an issue if necessary instead 👍