Add toggleTouchIdEnrollment function

[dpgraham]

Description

• We currently have a touchId function (https://github.com/appium/java-client/blob/3e9c9497e91b6db5f3454061d73fc534ed8b4e92/src/main/java/io/appium/java_client/ios/PerformsTouchID.java) that hits the /session/:sessionId/appium/simulator/touch_id endpoint
• We need a function like this that hits the toggleTouchIdEnrollment endpoint /session/:sessionId/appium/simulator/toggle_touch_id_enrollment(method: POST, no data params)
• For reference see Added toggleEnrollTouchID to commands appium-xcuitest-driver#402