Consistent look for libadwaita and gtk3 window controls

[cpuccino]

Currently: The window controls for default libadwaita apps look different from the fluent theme being used.

• Close button hover state for libadwaita doesn't have a red background
• Minimize and Maximize hover state for libadwaita has a "circle*" background

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Expected: Both should be consistent

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Minimal POC (Only tested on fluent-circle theme)

gtk4.css

headerbar windowhandle box windowcontrols button image {
  background-image: none;
  background-color: transparent;
  padding: 4px;
}

headerbar windowhandle box windowcontrols button:hover image {
  background-color: rgba(75, 75, 75, 0.7);
  color: white;
}

headerbar windowhandle box windowcontrols button.close:hover image {
  background-color: #E57373;
  color: white;
}

[Anduin2017]

@vinceliuice is this an issue from the theme or OS?