Fixes #14119 - Adjust bottom margin of bottomActionBar…

[dgmltn]

… in ConversationListFragment, CallLogFragment to accomodate nav bar

Contributor checklist

• I am following the Code Style Guidelines
• I have tested my contribution on these devices:

• Pixel 9, Android SDK 35
• Virtual device "Pixel 4a", Android SDK 30

• My contribution is fully baked and ready to be merged as is
• I ensure that all the open issues my contribution fixes are mentioned in the commit message of my first commit using the Fixes #1234 syntax

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Description

This adds a bottom margin to the bottomActionBar inside ConversationListFragment and CallLogFragment (via SignalBottomActionBarController) to accomodate Navigation Bars.

• I was a bit concerned that the SignalBottomActionBarController change would affect other bottom actionbars but I confirmed that it's used only inside the CallLogFragment.
• I tested on SDK 30 using both gesture navigation and 3 button navigation to make sure the nav bar height calculation was correct (even though ViewUtil.getNavigationBarHeight already existed).
• I used my judgement to determine an extra padding of 8dp between the nav bar and action bar looked the best. 16dp seemed too big.
• I considered moving adjustBottomMarginForNavBar to ViewUtil (especially since it just calls 3 ViewUtil methods anyway) but it seemed too specific to this use case. I could be convinced to move it there. LMK