fix: Remove imePadding modifier to internal scaffold box

[jsoberg]

fixes #1603
fixes #1767

BaseScaffold is applying imePadding() to an internal Box on all screen-level Composables. This is evidently unnecessary with our setup and applies double keyboard padding for older devices.

On my Samsung A10e, Android 9:

Before	After
BEFORE.mp4	AFTER.mp4

Also tested on my Samsung S23 Ultra to verify this change didn't affect devices that didn't have this issue.

[jamesarich]

@jsoberg have we tried how this works with edge to edge on 35? We'll eventually want to bump our target sdk up and we'll need to audit for edge to edge stuff since we're on material 2.