Clear all cells before executing notebook in the ci

Author: mcbarton

scripts/automated-notebook-run-script.py

@@ -86,6 +86,7 @@ def main():
     time.sleep(1)
 
     notebook_area.click()
+    actions.context_click(notebook_area).pause(0.1).send_keys(Keys.DOWN * 9).pause(0.1).send_keys(Keys.ENTER).pause(0.1).perform()
 
     # Select Kernel based on input
     kernel_button = driver.find_element(