### Apache Airflow Provider(s)

salesforce

### Versions of Apache Airflow Providers

apache-airflow-providers-salesforce==1!3.2.0

### Apache Airflow version

2.1.4

### Operating System

Debian GNU/Linux 10 (buster)

### Deployment

Astronomer

### Deployment details

_No response_

### What happened

Right now the `SalesforceHook` is requiring all of the extras for a Salesforce connection type in Airflow.

I am assuming this issue was never brought up before because users of this hook have been using the Airflow UI to make connections (which presents all extra fields), however with things such as Secrets Backends, it should be possible to set up a Salesforce connection URI without having to explicitly provide all of the extras.

The issue is the hook's author designed the hook's `get_conn` to pass in every extra value using an improper/invalid method of defaulting to None by using `or None` but still referencing the extras key directly. I tested this in as low as Python 2.7 and as high as Python 3.7 and in both versions if any one of these extras are not provided you will get a `KeyError`

https://github.com/apache/airflow/blob/e9a72a4e95e6d23bae010ad92499cd7b06d50037/airflow/providers/salesforce/hooks/salesforce.py#L137-L149

### What you expected to happen

Any extras value not provided should just default to None (or to `api.DEFAULT_API_VERSION` for the "version" extra). It should be possible to set up a Salesforce connection URI using a secrets backend without having to explicitly provide all of the extras.

### How to reproduce

Set up a secrets backend (such as via environment variable) and pass in the minimum connection values needed for "Password" connection type:

_(this is an example, no real passwords shown)_
`export AIRFLOW_CONN_SALESFORCE_DEFAULT='http://your_username:your_password@https%3A%2F%2Fyour_host.lightning.force.com?extra__salesforce__security_token=your_token'`

It will error with `KeyError: 'extra__salesforce__domain'` and keep resulting in key errors for each extras key until you finally provide all extras, like so:

_(this is an example, no real passwords shown)_
`export AIRFLOW_CONN_SALESFORCE_DEFAULT='http://your_username:your_password@https%3A%2F%2Fyour_host.lightning.force.com?extra__salesforce__security_token=your_token&extra__salesforce__domain=&extra__salesforce__instance=&extra__salesforce__instance_url=&extra__salesforce__organization_id=&extra__salesforce__version=&extra__salesforce__proxies=&extra__salesforce__client_id=&extra__salesforce__consumer_key=&extra__salesforce__private_key_file_path=&extra__salesforce__private_key='`

### Anything else

In addition to this, the `SalesforceHook` should also accept extras without the need for the `extra__salesforce__` prefix, like many other connections do.

### Are you willing to submit PR?

- [X] 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/providers/salesforce/hooks/salesforce.py
"""
        Get a list of all available fields for an object.
        :param obj: The name of the Salesforce object that we are getting a description of.
        :type obj: str
        :return: the names of the fields.
        :rtype: list(str)
        """
        obj_description = self.describe_object(obj)
        return [field['name'] for field in obj_description['fields']]
    def get_object_from_salesforce(self, obj: str, fields: Iterable[str]) -> dict:
        """
        Get all instances of the `object` from Salesforce.
        For each model, only get the fields specified in fields.
        All we really do underneath the hood is run:
            SELECT <fields> FROM <obj>;
        :param obj: The object name to get from Salesforce.
        :type obj: str
        :param fields: The fields to get from the object.
        :type fields: iterable
        :return: all instances of the object from Salesforce.
        :rtype: dict
        """
        query = f"SELECT {','.join(fields)} FROM {obj}"
        self.log.info(
            "Making query to Salesforce: %s",
            query if len(query) < 30 else " ... ".join([query[:15], query[-15:]]),
        )
        return self.make_query(query)
    @classmethod
    def _to_timestamp(cls, column: pd.Series) -> pd.Series: