Remove color setting from MassiveFab

This makes the button automatically adjust
according to what the user has set the primary
color to be.
Seems that with the default dark theme the cyan
makes the text not the same color as the Button,
but this still looks better than the statically
set colors from before.

MassiveFab.tsx

@@ -1,19 +1,16 @@
 import React, {useContext} from 'react';
-import {useColorScheme} from 'react-native';
 import {FAB} from 'react-native-paper';
-import {CombinedDarkTheme, CustomTheme} from './App';
+import {CustomTheme} from './App';
 
 export default function MassiveFab(
   props: Partial<React.ComponentProps<typeof FAB>>,
 ) {
-  const dark = useColorScheme() === 'dark';
   const {color} = useContext(CustomTheme);
 
   return (
     <FAB
       {...props}
       icon="add"
-      color={dark ? CombinedDarkTheme.colors.background : 'white'}
       style={{
         position: 'absolute',
         right: 10,