Update getting started theme picker images to reflect new themes (microsoft#180976)

* Update getting started theme picker assets to reflect new themes

* Update theme names

Author: daviddossett

src/vs/workbench/contrib/welcomeGettingStarted/common/media/dark.png

@@ -12,11 +12,11 @@ export default () => `
 	<div class="theme-picker-row">
 		<checkbox when-checked="setTheme:${ThemeSettingDefaults.COLOR_THEME_DARK}" checked-on="config.workbench.colorTheme == '${ThemeSettingDefaults.COLOR_THEME_DARK}'">
 			<img width="200" src="./dark.png"/>
-			${escape(localize('dark', "Dark"))}
+			${escape(localize('dark', "Dark Modern"))}
 		</checkbox>
 		<checkbox when-checked="setTheme:${ThemeSettingDefaults.COLOR_THEME_LIGHT}" checked-on="config.workbench.colorTheme == '${ThemeSettingDefaults.COLOR_THEME_LIGHT}'">
 			<img width="200" src="./light.png"/>
-			${escape(localize('light', "Light"))}
+			${escape(localize('light', "Light Modern"))}
 		</checkbox>
 	</div>
 	<div class="theme-picker-row">