Renaming the Follow button to "Follow back" when followed by user (#5281)

* Renaming the follow button to follow back when followed by user

* Fixing conditions and reusing existing translation

src/screens/Profile/Header/ProfileHeaderStandard.tsx

@@ -219,6 +219,8 @@ let ProfileHeaderStandard = ({
                 <ButtonText>
                   {profile.viewer?.following ? (
                     <Trans>Following</Trans>
+                  ) : profile.viewer?.followedBy ? (
+                    <Trans>Follow Back</Trans>
                   ) : (
                     <Trans>Follow</Trans>
                   )}

src/view/com/profile/FollowButton.tsx

@@ -61,7 +61,7 @@ export function FollowButton({
         label={_(msg({message: 'Unfollow', context: 'action'}))}
       />
     )
-  } else {
+  } else if (!profile.viewer.followedBy) {
     return (
       <Button
         type={unfollowedType}
@@ -70,5 +70,14 @@ export function FollowButton({
         label={_(msg({message: 'Follow', context: 'action'}))}
       />
     )
+  } else {
+    return (
+      <Button
+        type={unfollowedType}
+        labelStyle={labelStyle}
+        onPress={onPressFollow}
+        label={_(msg({message: 'Follow Back', context: 'action'}))}
+      />
+    )
   }
 }