[Settings] Code refactor - remove unused import lines

Remove some unused import lines within source code based on
https://source.android.com/setup/contribute/code-style

Bug: 182867979
Test: build pass
Change-Id: I76dbcfa9e5b435b2838401dfee15b12f472d07d0

src/com/android/settings/deviceinfo/StorageVolumePreference.java

@@ -19,7 +19,6 @@ package com.android.settings.deviceinfo;
 import android.app.usage.StorageStatsManager;
 import android.content.Context;
 import android.content.res.ColorStateList;
-import android.graphics.Color;
 import android.graphics.drawable.Drawable;
 import android.os.storage.StorageManager;
 import android.os.storage.VolumeInfo;