Deprecate JapaneseCalendar.CURRENT_ERA

In the future, if the era changes in Japan, CURRENT_ERA
on old Android devices will be incorrect.

Thus, Android app developer should not use this API.

Bug: 77850660
Test: m droid
Change-Id: I9ee640bccc83a73c94ac76138597f09f05af8796
diff --git a/api/current.txt b/api/current.txt
index 7a506ee..19eabbc 100755
--- a/api/current.txt
+++ b/api/current.txt
@@ -20918,7 +20918,7 @@
     ctor public JapaneseCalendar(int, int, int, int);
     ctor public JapaneseCalendar(int, int, int);
     ctor public JapaneseCalendar(int, int, int, int, int, int);
-    field public static final int CURRENT_ERA;
+    field @Deprecated public static final int CURRENT_ERA;
     field public static final int HEISEI;
     field public static final int MEIJI;
     field public static final int SHOWA;