feat: Add option to always show cancel button

[hmhobbs]

This adds a boolean option stickyCancel to showActionSheetWithOptions that moves the cancel button outside of the ScrollView in the custom action sheet containing the other options. This emulates the default behavior on iOS. It is especially useful for action sheets with a long list of options. This also adds another button to the example app to demonstrate this behavior.

With stickyCancel: true

with stickyCancel: false

[hmhobbs]

This is to address the following issues:

319 #327