Check task.isResizeable() instead of the resize mode directly

The resize mode doesn't take into account developer settings override.

Bug: 27390258
Change-Id: Id161ceb4f143f982f6bec3f915655bb66949ddd3
diff --git a/services/core/java/com/android/server/am/ActivityStackSupervisor.java b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
index 20f8285..c7fc5e2 100644
--- a/services/core/java/com/android/server/am/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
@@ -2186,7 +2186,7 @@
 
         final int resizeMode = task.mResizeMode;
 
-        if (stackId == DOCKED_STACK_ID && resizeMode == RESIZE_MODE_UNRESIZEABLE) {
+        if (stackId == DOCKED_STACK_ID && !task.isResizeable()) {
             // We don't allow moving a unresizeable task to the docked stack since the docked
             // stack is used for split-screen mode and will cause things like the docked divider to
             // show up. We instead leave the task in its current stack or move it to the fullscreen