GrantleeThemeTest::testRenderTemplate(color): update expected link bg color
Seems calculation formula of the color by KColorScheme has changed a bit since the test was written
I could not trace down any related changes in https://invent.kde.org/frameworks/kconfigwidgets/-/blob/master/src/kcolorscheme.cpp#L449 and https://invent.kde.org/frameworks/kguiaddons/-/blob/master/src/colors/kcolorutils.cpp#L105 though, but I suspect somewhere some value rounding was changed perhaps and resulted in the off by 1 for r and g?