Prevent counting items more than once during multi-select.

Test: Ran full test suite
Bug: 35099635
Change-Id: I9b447297987150bbf8354d28edf518f297ee95f0
diff --git a/src/com/android/documentsui/selection/SelectionManager.java b/src/com/android/documentsui/selection/SelectionManager.java
index d6fcaef..ed1758c 100644
--- a/src/com/android/documentsui/selection/SelectionManager.java
+++ b/src/com/android/documentsui/selection/SelectionManager.java
@@ -500,7 +500,7 @@
             }
             if (selected) {
                 boolean canSelect = canSetState(id, true);
-                if (canSelect) {
+                if (canSelect && !mSelection.mSelection.contains(id)) {
                     mSelection.mProvisionalSelection.add(id);
                 }
             } else {