manager: free some lambdas' capture ressources

tasks, event handlers use lambdas as callback.
These lambdas may have captured some ressources
that need to be released before the some others, like pjsip.

this patch clears all this tasks/handlers during the finish().

Change-Id: I5449fe8923c06ad85c16bbdf584f686a4ba94188

src/manager.cpp

@@ -789,6 +789,12 @@ Manager::finish() noexcept
         }
 
         pimpl_->ice_tf_.reset();
+
+        // Flush remaining tasks (free lambda' with capture)
+        pimpl_->pendingTaskList_.clear();
+        pimpl_->scheduledTasks_.clear();
+        pimpl_->eventHandlerMap_.clear();
+
         pj_shutdown();
         ThreadPool::instance().join();
     } catch (const VoipLinkException &err) {