Update Notification.shortCriticalText doc to recommend 7 chars, not 5.

If we expect a lot of apps to put times like "10:15pm", we should recommend 7 characters.

Bug: 337261753
Change-Id: I3ea89f544628b64222bac3829752793a3a9236c0
Flag: android.app.api_rich_ongoing
Test: compiles
diff --git a/core/java/android/app/Notification.java b/core/java/android/app/Notification.java
index 0381ee0..3d9c55c 100644
--- a/core/java/android/app/Notification.java
+++ b/core/java/android/app/Notification.java
@@ -5003,7 +5003,7 @@
 
         /**
          * Sets a very short string summarizing the most critical information contained in the
-         * notification. Suggested max length is 5 characters, and there is no guarantee how much or
+         * notification. Suggested max length is 7 characters, and there is no guarantee how much or
          * how little of this text will be shown.
          */
         @FlaggedApi(Flags.FLAG_API_RICH_ONGOING)