feat(non linear font scaling): add TypedValue.deriveDimension()

deriveDimension() is the inverse of TypedValue.applyDimension(), so devs
don't hardcode equations to convert px -> dp etc. The reason we need to
discourage hardcoding is to ensure that devs are using the correct non-
linear font scaling curves calculated by applyDimension().

Test: atest FrameworksCoreTests:android.content.res.FontScaleConverterTest && atest FrameworksCoreTests:android.util.TypedValueTest

Bug: b/237558231

Change-Id: Id4252b6ddcb6183c7b4fc3489918bcfd95ee1103