[Chore] Fix problems detected by VSCode

[manuel-plavsic]

This PR fixes all the remaining problems that VSCode detects (note: I used the main channel, maybe some of the warnings do not appear yet on stable).

I was unsure whether to remove the keys entirely or to replace

ignore: unused_element

with the new:

ignore: unused_element_parameter

Since the keys are not used and it may be slightly confusing to keep them, I decided to remove them.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (c2c53ed) to head (40cded2).
Report is 1 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff            @@
##               dev       #99   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           21        21           
  Lines         1194      1194           
=========================================
  Hits          1194      1194           

Files with missing lines	Coverage Δ
...ckages/flutter_solidart/lib/src/widgets/solid.dart	100.00% <ø> (ø)

[nank1ro]

Are you using the latest stable of Flutter?

[manuel-plavsic]

The latest main:

> flutter --version
Flutter 3.28.0-2.0.pre.38587 • channel main • https://github.com/flutter/flutter.git
Framework • revision b15625ca92 (35 hours ago) • 2024-12-27 15:26:24 -0800
Engine • revision b15625ca92
Tools • Dart 3.7.0 (build 3.7.0-267.0.dev) • DevTools 2.41.0

[nank1ro]

The problem is that they deprecated and replaced stuff of main, but on stable the new stuff is not there yet, this PR cannot land

[nank1ro]

LGTM