As part of #18364 this commit ebd5152 suppressed all unused material scaffold padding parameter Lint warnings.

• Warning Message: Content padding parameter it is not used
• Explanation: The content lambda in Scaffold has a padding parameter which will include any inner padding for the content due to app bars. If this parameter is ignored, then content may be obscured by the app bars resulting in visual issues or elements that can't be interacted with.

These Lint warnings were suppressed, that is, instead of them being resolved, since a resolution would require a proper investigation and testing. As such, it was decided to ignore those as out of scope, for the time being, and so as to not introduce any (potential) breaking changes to any scaffold related functionality overall.

This issue is exactly about that, that is, to try and resolve as many of the currently suppressed UnusedMaterialScaffoldPaddingParameter Lint warnings.

Cc @thomashorta @ovitrif