Lint warnings housekeeping

#384 in iced-rs/iced_aw — merged 2025-12-28

Fixed lint errors

• src/widget/card.rs - Fixed 8 lint errors
• src/widget/menu/menu_bar_overlay.rs - Fixed 3 lint errors
• src/widget/menu/menu_tree.rs - Fixed 2 lint errors
• src/widget/menu/menu_bar.rs - Fixed 1 lint error
• src/widget/menu/common.rs - Fixed 1 lint error
• src/widget/badge.rs - Fixed 1 lint error

Fixed tests warnings and errors

• Fixed several warnings with unit and integration tests

Updated test workflow

• test.yml updated to run cargo test --lib --tests --bins

All test pass without warnings or errors

# run all tests
cargo test --lib --tests --bins