{Documentation} Mark "Sanity check" as optional. (#6056)
{Documentation} Mark "Sanity check" as optional. (#6056)

The Sanity Check steps seem to be a bunch of required steps that aren't
necessary if the release engineer has followed the previous instructions.
Instead, it can be an optional set of helpful commands.
material-components/material-components-ios,material-components/material-components-ios,material-components/material-components-ios,material-components/material-components-ios,material-components/material-components-ios