## Is your feature request related to a problem?

Right now, if you try to invite someone who's already invited (or a user) you get the following error message:
![image](https://user-images.githubusercontent.com/1727427/98357556-adff4a80-2025-11eb-9f4d-ba748155d036.png)

## Describe the solution you'd like

The server itself does return a useful error message, so we could just display that

## Describe alternatives you've considered



## Additional context



#### *Thank you* for your feature request – we love each and every one!

posthog/api/organization_invite.py
if OrganizationMembership.objects.filter(
            organization_id=self.context["organization_id"], user__email=validated_data["target_email"]
        ).exists():
            raise exceptions.ValidationError("A user with this email address already belongs to the organization.")
        if OrganizationInvite.objects.filter(
            organization_id=self.context["organization_id"], target_email=validated_data["target_email"]
        ).exists():
            raise exceptions.ValidationError(
                "An invite intended for this email already is active in this organization."
            )
        invite: OrganizationInvite = OrganizationInvite.objects.create(
            organization_id=self.context["organization_id"],
            created_by=self.context["request"].user,
            target_email=validated_data["target_email"],
        )
        if is_email_available(with_absolute_urls=True):
            invite.emailing_attempt_made = True
            send_invite.delay(invite_id=invite.id)
            invite.save()
        return invite
class OrganizationInviteViewSet(