updated start proto to return exception strings, updated grpc start session to exist early when a failure is found, updated coretk ui to not switch ui to running when start fails and display error dialog

daemon/core/gui/toolbar.py

@@ -236,11 +236,12 @@ class Toolbar(ttk.Frame):
         :return: nothing
         """
         self.app.canvas.hide_context()
-        self.app.statusbar.core_alarms.clear()
         self.app.statusbar.progress_bar.start(5)
         self.app.canvas.mode = GraphMode.SELECT
         thread = threading.Thread(target=self.app.core.start_session)
         thread.start()
+
+    def set_runtime(self):
         self.runtime_frame.tkraise()
         self.click_runtime_selection()