Closes #26973: adjust wallpaper onboarding ui (#26974)

Co-authored-by: mike a <mavduevskiy@gmail.com>
Co-authored-by: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

app/src/main/java/org/mozilla/fenix/wallpapers/WallpaperOnboarding.kt

@@ -55,10 +55,10 @@ fun WallpaperOnboarding(
 ) {
     Surface(
         color = FirefoxTheme.colors.layer2,
-        shape = RoundedCornerShape(topStart = 16.dp, topEnd = 16.dp),
+        shape = RoundedCornerShape(topStart = 8.dp, topEnd = 8.dp),
     ) {
         Column(
-            modifier = Modifier.padding(16.dp),
+            modifier = Modifier.padding(horizontal = 32.dp, vertical = 16.dp),
             horizontalAlignment = Alignment.CenterHorizontally,
         ) {
             Icon(
@@ -117,8 +117,6 @@ fun WallpaperOnboarding(
                     style = FirefoxTheme.typography.button,
                 )
             }
-
-            Spacer(modifier = Modifier.height(12.dp))
         }
     }
 }

app/src/main/res/values/styles.xml

@@ -566,7 +566,7 @@
     <style name="HomeOnboardingDialogStyle" parent="DialogStyleBase"/>
     <style name="WallpaperOnboardingDialogStyle" parent="DialogStyleBase">
         <item name="android:windowIsFloating">true</item>
-        <item name="android:backgroundDimAmount">0.02</item>
+        <item name="android:backgroundDimAmount">0.06</item>
     </style>
     <style name="CreateShortcutDialogButton" parent="Widget.MaterialComponents.Button.TextButton.Dialog">
         <item name="android:layout_width">wrap_content</item>