Fix image button padding on hover

[newcomb-luke]

This PR addresses one issue that has been encountered by multiple people where image buttons don't display correctly when hovering. This updates 2 lines of code that fix the problem as shown in the image below.

There are no clippy warnings.

./sh/check.sh was not able to be completed for some unrelated error below in speech-dispatcher:

error[E0308]: mismatched types
  --> /home/luke/.cargo/registry/src/github.com-1ecc6299db9ec823/speech-dispatcher-0.12.0/src/lib.rs:35:13
   |
35 |     Male1 = SPDVoiceType::SPD_MALE1,
   |             ^^^^^^^^^^^^^^^^^^^^^^^ expected `u32`, found `i32`

The fixed image buttons shown:

Closes #1528.

[emilk]

thanks!