Flattened the color/dark mode settings

[sgayangi]

What

• Removed the shadow of the widgets for changing darkmode and color theme of the app in the user preferences screen

Screenshot

Fixes bug(s)

• Flatten color/dark mode settings #919

Part of

• Flatten color/dark mode settings #919
  (please be as granular as possible)

[teolemon]

@sgayangi : the CHANGELOG is generated automatically, as long as your Pull Request is semantic

[sgayangi]

@sgayangi : the CHANGELOG is generated automatically, as long as your Pull Request is semantic

I'm really sorry, I didn't know that. I reverted that change, I hope that will fix it.

[M123-dev]

Heyy, thanks for the PR @sgayangi, the code looks good.

Just a note, we have some predefined spaces in design_constants.dart I'd be if we'd use them here as well so that we don't mix different values throughout the app

[M123-dev]

Thanks for the change @sgayangi, everything looks good now 👍🏼

[sgayangi]

Thank you for the feedback :) looking forward to contributing more