Make `WorkQuery.Builder` final.

Fixes: b/152864572 partly.
Test: Existing unit tests pass.
Change-Id: Ia1c511c6c2a54f81d42ede18afa79dadebb38711
diff --git a/work/workmanager/api/public_plus_experimental_current.txt b/work/workmanager/api/public_plus_experimental_current.txt
index 4a0ea1c..536ebb1 100644
--- a/work/workmanager/api/public_plus_experimental_current.txt
+++ b/work/workmanager/api/public_plus_experimental_current.txt
@@ -303,7 +303,7 @@
     method public java.util.List<java.lang.String!> getUniqueWorkNames();
   }
 
-  public static class WorkQuery.Builder {
+  public static final class WorkQuery.Builder {
     method public androidx.work.WorkQuery.Builder addStates(java.util.List<androidx.work.WorkInfo.State!>);
     method public androidx.work.WorkQuery.Builder addTags(java.util.List<java.lang.String!>);
     method public androidx.work.WorkQuery.Builder addUniqueWorkNames(java.util.List<java.lang.String!>);