Register the DatabaseUiExecutor for shutdown by the LifecycleManager.

See issue #3612607.

briar-api/src/net/sf/briar/api/android/DatabaseUiExecutor.java

@@ -1,6 +1,7 @@
 package net.sf.briar.api.android;
 
 import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
 import static java.lang.annotation.ElementType.PARAMETER;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
 
@@ -13,6 +14,6 @@ import com.google.inject.BindingAnnotation;
  * Annotation for injecting the executor for accessing the database from the UI.
  */
 @BindingAnnotation
-@Target({ FIELD, PARAMETER })
+@Target({ FIELD, METHOD, PARAMETER })
 @Retention(RUNTIME)
 public @interface DatabaseUiExecutor {}