Provides text preview whenever the seekbar progress changes

When the font scale is modified by the icon buttons, we also like to show
the preview of text first to avoid the feeling of lag for users to wait
for the system font size change.

Bug: 279525588
Test: manually - attach the video to the bug
Change-Id: I8da85eb9b264f331c4347a87e2107d52872f4274

packages/SystemUI/src/com/android/systemui/accessibility/fontscaling/FontScalingDialog.kt

@@ -107,13 +107,13 @@ class FontScalingDialog(
                 var isTrackingTouch = false
 
                 override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
+                    // Always provide preview configuration for text first when there is a change
+                    // in the seekbar progress.
+                    createTextPreview(progress)
+
                     if (!isTrackingTouch) {
                         // The seekbar progress is changed by icon buttons
                         changeFontSize(progress, CHANGE_BY_BUTTON_DELAY_MS)
-                    } else {
-                        // Provide preview configuration for text instead of changing the system
-                        // font scale before users release their finger from the seekbar.
-                        createTextPreview(progress)
                     }
                 }