Tweak copy to remove remaining uses of sign up (#7987)

* tweak copy in Deactivated.tsx

* tweak copy in Policies.tsx

* tweak comment in createNativeStackNavigatorWithAuth.tsx

* tweak copy in LoginForm.tsx

* tweak copy in StarterPackLandingScreen.tsx

* format

* Apply suggestions from code review

Co-authored-by: Hailey <hailey@blueskyweb.xyz>

* Update src/screens/StarterPack/StarterPackLandingScreen.tsx

Co-authored-by: surfdude29 <149612116+surfdude29@users.noreply.github.com>

* Update src/screens/StarterPack/StarterPackLandingScreen.tsx

Co-authored-by: surfdude29 <149612116+surfdude29@users.noreply.github.com>

---------

Co-authored-by: Hailey <hailey@blueskyweb.xyz>

src/screens/StarterPack/StarterPackLandingScreen.tsx

@@ -300,14 +300,14 @@ function LandingScreenLoaded({
             ) : null}
           </View>
           <Button
-            label={_(msg`Signup without a starter pack`)}
+            label={_(msg`Create an account without using this starter pack`)}
             variant="solid"
             color="secondary"
             size="large"
             style={[a.py_lg]}
             onPress={onJoinWithoutPress}>
             <ButtonText>
-              <Trans>Signup without a starter pack</Trans>
+              <Trans>Create an account without using this starter pack</Trans>
             </ButtonText>
           </Button>
         </View>