Add default brightness config to dumpsys display

Test: manual: Booted device and ran adb dumpsys display checked for config.
Bug: 131735749
Change-Id: Id6957807487381ddf84bb40cf12e2b36b374daf9

services/core/java/com/android/server/display/BrightnessMappingStrategy.java

@@ -778,6 +778,7 @@ public abstract class BrightnessMappingStrategy {
             pw.println("  mAutoBrightnessAdjustment=" + mAutoBrightnessAdjustment);
             pw.println("  mUserLux=" + mUserLux);
             pw.println("  mUserBrightness=" + mUserBrightness);
+            pw.println("  mDefaultConfig=" + mDefaultConfig);
         }
 
         private void computeSpline() {