[ELI5] change sign in to create account (#6931)

* change sign in to create account

* alf buttons on native bottom bar

* manually edit .po file

src/view/shell/NavSignupCard.tsx

@@ -44,12 +44,12 @@ let NavSignupCard = ({}: {}): React.ReactNode => {
       <View style={[a.flex_row, a.flex_wrap, a.gap_sm, a.pt_md]}>
         <Button
           onPress={showCreateAccount}
-          label={_(msg`Sign up`)}
+          label={_(msg`Create account`)}
           size="small"
           variant="solid"
           color="primary">
           <ButtonText>
-            <Trans>Sign up</Trans>
+            <Trans>Create account</Trans>
           </ButtonText>
         </Button>
         <Button