Create more common_* common strings (#11439)

src/theme.ts

@@ -77,9 +77,9 @@ export function isHighContrastTheme(theme: string): boolean {
 
 export function enumerateThemes(): { [key: string]: string } {
     const BUILTIN_THEMES = {
-        "light": _t("Light"),
+        "light": _t("common|light"),
         "light-high-contrast": _t("Light high contrast"),
-        "dark": _t("Dark"),
+        "dark": _t("common|dark"),
     };
     const customThemes = SettingsStore.getValue("custom_themes") || [];
     const customThemeNames: Record<string, string> = {};