### Apache Airflow version

2.2.0

### Operating System

Debian buster

### Versions of Apache Airflow Providers

_No response_

### Deployment

Astronomer

### Deployment details

astro dev start

### What happened

When I have tried to duplicate a connection first time it has created a connection with hello_copy1 and duplicating the same connection second time giving me an error of 
```Connection hello_copy2 can't be added. Integrity error, probably unique constraint.```




### What you expected to happen

It should create a connection with name hello_copy3 or the error message should be more user friendly.

### How to reproduce

https://github.com/apache/airflow/pull/15574#issuecomment-912438705

### Anything else

Suggested Error 
```
Connection hello_copy2 can't be added because it already exists.
```
or
Change the number logic in _copyN so the new name will be always unique.


### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

airflow/www/views.py
"""List providers."""
        providers_manager = ProvidersManager()
        providers = []
        for pi in providers_manager.providers.values():
            provider_info = pi[1]
            provider_data = {
                "package_name": provider_info["package-name"],
                "description": self._clean_description(provider_info["description"]),
                "version": pi[0],
                "documentation_url": get_doc_url_for_provider(provider_info["package-name"], pi[0]),
            }
            providers.append(provider_data)
        title = "Providers"
        doc_url = get_docs_url("apache-airflow-providers/index.html")
        return self.render_template(
            'airflow/providers.html',
            providers=providers,
            title=title,
            doc_url=doc_url,
        )
    def _clean_description(self, description):
        def _build_link(match_obj):
            text = match_obj.group(1)
            url = match_obj.group(2)
            return markupsafe.Markup(f'<a href="{url}">{text}</a>')
        cd = markupsafe.escape(description)
        cd = re.sub(r"`(.*)[\s+]+&lt;(.*)&gt;`__", _build_link, cd)
        cd = re.sub(r"\n", r"<br>", cd)
        return markupsafe.Markup(cd)
class PoolModelView(AirflowModelView):