[Navigation Material] Clicking back when bottom sheet is displayed closes host activity too

[JesusM]

Description

Issue present on navigation material library, version 0.31.6-rc

When a bottom sheet is visible, clicking back not only dismisses it but also closes its host activity.
Issue is present on 1.5stable branch, whereas main works as expected.

Steps to reproduce

1.- Checkout accompanist samples repo, on branch 1.5stable
2.- Run "Navigation: Bottom Sheets" sample
3.- When a bottom sheet is displayed, click "back"

Expected behavior

Only the visible bottom sheet should be dismissed, and host activity should remain visible.

Additional context

[JesusM]

Seems closed as part of latest v0.32.0 release, so closing this.