Show underline when text show a link

Hyperlinked text should have underline instead of using color only,
such that color blind users are able to compare to the surrounding text.

Change-Id: I7e93f76ebd40077710385e8670176e878b021ef8
Fix: 148839397
Test: visual see link in "Skip songs", "Silence interruptions", "Reach to check phone".

src/com/android/settings/LinkifyUtils.java

@@ -74,7 +74,7 @@ public class LinkifyUtils {
             @Override
             public void updateDrawState(TextPaint ds) {
                 super.updateDrawState(ds);
-                ds.setUnderlineText(false);
+                ds.setUnderlineText(true);
             }
         };
         spannableContent.setSpan(spannableLink, beginIndex, endIndex,