Fix b/242252080: Add padding space on the top of the battery chart

screenshot: https://screenshot.googleplex.com/9XU9Yiwv9YAVd46.png

Bug: 242252080
Test: manual
Change-Id: I81730168337b311600a12b844753848c21105d46

src/com/android/settings/fuelgauge/batteryusage/BatteryChartView.java

@@ -529,7 +529,8 @@ public class BatteryChartView extends AppCompatImageView implements View.OnClick
         final float trapezoidBottom =
                 getHeight() - mIndent.bottom - mDividerHeight - mDividerWidth
                         - mTrapezoidVOffset;
-        final float availableSpace = trapezoidBottom - mDividerWidth * .5f - mIndent.top;
+        final float availableSpace =
+                trapezoidBottom - mDividerWidth * .5f - mIndent.top - mTrapezoidVOffset;
         final float unitHeight = availableSpace / 100f;
         // Draws all trapezoid shapes into the canvas.
         final Path trapezoidPath = new Path();