Use numAllAppsColumns to calculate height of all apps icons

Additionally opens up access of some fields to allow them to be overridden.

Test: Manually verified that Launcher3 layout does not change

Launcher3 APKs: https://drive.google.com/drive/folders/1hBcZU9xou4tZJxbTmkya_LyBbD2oYuwV?resourcekey=0-R0I1IQ2rSUIEfPjW8S_ppA&usp=sharing

Bug: 216150572

Change-Id: I4b97a7e9e15973fc5aa70a4b98f0b73dd5bf3c17