I don't have floor sensors, but you should be able to remove it from the alarm list.
From that alarm list, Press the Icon that looks like an outlet, then you should see 3 different alarm types. Select the one that says something like "Email Alarm" (the name is programmable, so I'm not sure what yours says)
That will bring up the alarm program, which you should see the floor sensor and you should be able to remove it.