Changed background colours in adwaita-dark theme to updated colours from GNOME 48 (#14695)

Co-authored-by: Theodor Levi Halldorsson <[email protected]>

Author: theodorlevi

runtime/themes/adwaita-dark.toml

@@ -133,9 +133,9 @@ green_4 = "#2EC27E"
 green_5 = "#26A269"
 green_6 = "#1F7F56"
 green_7 = "#1C6849"
-libadwaita_dark = "#1D1D1D"
-libadwaita_dark_alt = "#303030"
-libadwaita_popup = "#282828"
+libadwaita_dark = "#1d1d20"
+libadwaita_dark_alt = "#28282c"
+libadwaita_popup = "#36363a"
 light_1 = "#FFFFFF"
 light_2 = "#FCFCFC"
 light_3 = "#F6F5F4"