FAB should have a shadow at elevation level 3

[ericpoulinnz]

Current behaviour

When in M3, the shadow of the FAB is at level 6.

Expected behaviour

According to M3 spec, the FAB should have a shadow of level 3. I reported this for the AnimatedFAB back in #3805 and it seems to only have been fixed for the Animated version.

Your Environment

software	version
react-native	0.71.8
react-native-paper	0.5.8