manager: led priority is optional

The default priority was "Blink" but now the priority is optional.

This helps to implement group priority.
So if someone wants to use group priority they can do so, without the
default led priority getting in the way.

The led priority can still be assigned as "Blink" explicitly if needed.

Change-Id: I9336487bcc2edc0b3308ee76eb5330b8222b7f25
Signed-off-by: Alexander Hansen <alexander.hansen@9elements.com>
diff --git a/manager/manager.cpp b/manager/manager.cpp
index 18d257b..a5ac6b3 100644
--- a/manager/manager.cpp
+++ b/manager/manager.cpp
@@ -26,7 +26,9 @@
 
     auto currentAction = newState[action.name];
 
-    if (currentAction.action == action.priority)
+    const bool hasPriority = currentAction.priority.has_value();
+
+    if (hasPriority && currentAction.action == action.priority)
     {
         // if the current action is already the priority action,
         // we cannot override it