Fix capitalization for deprecation messages and a few comments in MDCAlertControllerView.
Fix capitalization for deprecation messages and a few comments in MDCAlertControllerView.

PiperOrigin-RevId: 302471807

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