Material 3: Snackbar bottom margin too large (insets for nav bar, but shouldn't)

[UweTrottmann]

Follow-ups from #884.

• [x] Draw behind system bars in MovieDetailsActivity.
• [x] Comments: use round images.
• [x] Use cards to separate panes on wide layouts. https://developer.android.com/large-screens/gallery/productivity
  • [x] Episodes
  • [x] People
• [ ] Snackbars not moved if button bar navigation is shown (obvious, since they adjust to the attached parent, which draws behind).
• [ ] Update snackbar in ShowsActivityImpl does adjust for navigation bar, but it shouldn't.
  • This is similar to https://github.com/material-components/material-components-android/issues/3446 (but that uses an anchor view, where it's odd that it still applies the extra margin). Commented there.

[UweTrottmann]

Snackbars:

• Removing the window inset listener kind of works ViewCompat.setOnApplyWindowInsetsListener(snackbar.view, null), however the layout has large top and bottom padding then?!
• Forcefully setting bottom margin to 0 does not work as the insets seem to be applied later.