Add symlink test

[davc0n]

Tried to figure out hyprwm/hyprlock#657 w/o success.
This PR adds a symlink test btw.

1: Test timeout computed to be: 1500
1: Loaded ./resource/images/hyprland.jpg successfully: Image is 4096x4096 of type image/jpeg
1: Passed tryLoadImage(file.path()). Got 1
1: Loaded ./resource/images/hyprland.png successfully: Image is 4096x4096 of type image/png
1: Passed tryLoadImage(file.path()). Got 1
1: Loaded ./resource/images/hyprland.jxl successfully: Image is 4096x4096 of type image/jxl
1: Passed tryLoadImage(file.path()). Got 1
1: Loaded ./resource/images/hyprland.webp successfully: Image is 4096x4096 of type image/webp
1: Passed tryLoadImage(file.path()). Got 1
1: Loaded ./resource/images/hyprland.symlink successfully: Image is 4096x4096 of type image/png
1: Passed tryLoadImage(file.path()). Got 1
1/1 Test #1: Image ............................   Passed    4.91 sec

100% tests passed, 0 tests failed out of 1

[PaideiaDilemma]

@davc0n hasn't that been fixed in #1???

I feel like the use in the hyprlock issue is probably using a tagged release of hyprgraphics, so it's not there yet.

[davc0n]

Yes it's possible