### Apache Airflow version

2.7.1

### What happened

Airflow's postgres connection configuration form has a field called  'schema'  which is misguiding as values mentioned here is used to refer to the database name instead of the schema name. It should be correctly named to 'database' or 'dbname'

### What you think should happen instead

_No response_

### How to reproduce

create a connection on the web UI and choose connection type as postgres.
Have a dag connect to an postgres server with multiple databases
provide the database name in the 'schema' field of the connection form- this would work if nothing else is incorrect in the etl
now change the value in the schema field of the connection form to refer to a schema- this will fail unexpectedly as the schema name field actually points to the database name.

### Operating System

Windows and Linux

### Versions of Apache Airflow Providers

2.71

### Deployment

Docker-Compose

### Deployment details

_No response_

### Anything else

_No response_

### 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)

"""Establishes a connection to a postgres database."""
        conn_id = getattr(self, self.conn_name_attr)
        conn = deepcopy(self.connection or self.get_connection(conn_id))
        
        if conn.extra_dejson.get("iam", False):
            conn.login, conn.password, conn.port = self.get_iam_token(conn)
        conn_args = {
            "host": conn.host,
            "user": conn.login,
            "password": conn.password,
            "dbname": self.database or conn.schema,
            "port": conn.port,
        }
        raw_cursor = conn.extra_dejson.get("cursor", False)
        if raw_cursor:
            conn_args["cursor_factory"] = self._get_cursor(raw_cursor)
        if self.options:
            conn_args["options"] = self.options
        for arg_name, arg_val in conn.extra_dejson.items():
            if arg_name not in [
                "iam",
                "redshift",
                "cursor",
                "cluster-identifier",
                "aws_conn_id",
            ]:
                conn_args[arg_name] = arg_val
        self.conn = psycopg2.connect(**conn_args)
        return self.conn
    def copy_expert(self, sql: str, filename: str) -> None: