Fix Snackbar position when keyboard is visible

[henni99]

Fix #1864

• Calculates the precise bottom padding required above the IME by using onGloballyPositioned to determine the component’s position relative to the root layout height.

• Incorporates WindowInsets.navigationBars to exclude the navigation bar height, ensuring that only the actual IME area is considered for padding.

• Combines Modifier.imePadding() with Modifier.consumeWindowInsets(), but supplies only the necessary padding to prevent unintended layout jumps.