Cherry-pick fixes from feature/10113_thetain_problem into next

Changes:

    refs #10113. Set angle to none.
    (cherry picked from commit eefb823)

    refs #10113. Fix spelling.
    (cherry picked from commit 4dc9c2e)

Code/Mantid/scripts/Interface/ui/reflectometer/refl_gui.py

@@ -914,6 +914,11 @@ def _do_run(self, runno, row, which):
             transmission_ws = mtd[transrun_named]
 
         angle = str(self.tableMain.item(row, which * 5 + 1).text())
+
+        # Explicitly set the angle to None so that the workflow algorithm doesn't try to interpret it.
+        if not angle:
+            angle = None
+
         loadedRun = runno
         if load_live_runs.is_live_run(runno):
             load_live_runs.get_live_data(config['default.instrument'], frequency = self.live_freq, accumulation = self.live_method)