Port yuzu-emu/yuzu#3339: "GUI: fix minor issues with dark themes + rename and reorder themes"

[FearlessTobi]

See yuzu-emu/yuzu#3339 for more details.

Original description:
This PR fixes few minor UI issues with dark themes also trying to mimic more "Default" ("Light") mode styling and component sizes to avoid resize on theme change. The following changes has been made:

• mimic "Default" theme list headers styling - use list background color, border omission, no extra padding - Screenshot 1
• decrease contrast of even rows on the lists to mimic "Default" theme styling and differentiate those rows more from Status Bar or Filter Bar - Screenshot 1
• update tabs minimal size and padding to roughly match "Default" theme styling - Screenshot 2
• fix Main Menu and Context Menu (ex. game row) checkbox position and items padding - Screenshot 3
• fix ComboBox currently selected value being repositioned on options list open (only "Dark" themes seems affected) - Preview 1

I have also changed the themes names and reordered them to make it even more obvious for user how the theme will be looking like. It's completely optional change, even rather proposition, which I can ditch if you don't like it.

Currently themes list looks like:

• Default
• Dark
• Colorful
• Colorful Dark

Proposed names and order (also visible in Preview 1):

• Light
• Light Colorful
• Dark
• Dark Colorful

I'm open to any suggestions and I would like to try to fix some more themes issues if you have experienced any.

Screenshot 1

Screenshot 2

Screenshot 3

Preview 1

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This change is 

[FearlessTobi]

Any review?

[zhaowenlan1779]

Did not really read the stylesheet, but it looks good