Messaging: Add "Mark as read" quick action for message notifications

Signed-off-by: Luca Stefani <luca.stefani.ge1@gmail.com>
Change-Id: I7194dca022e5062926fa35709de282721ca64320

res/drawable/ic_wear_read.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:height="24dp"
+    android:width="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="#ffffff"
+        android:pathData="M0.41,13.41L6,19L7.41,17.58L1.83,12M22.24,5.58L11.66,16.17L7.5,12L6.07,13.41L11.66,19L23.66,7M18,7L16.59,5.58L10.24,11.93L11.66,13.34L18,7Z" />
+</vector>

res/values/strings.xml

@@ -236,6 +236,8 @@
         <item quantity="one">New message</item>
         <item quantity="other"><xliff:g id="messages">%d</xliff:g> new messages</item>
     </plurals>
+    <!-- Mark message as read -->
+    <string name="notification_mark_as_read">Mark as read</string>
 
     <!-- Text for starting a new conversation button in the compose UI -->
     <string name="start_conversation">Start</string>