fix:Change the federated connection function name (auth0#674)

### Changes

- Modified the function name from `federated_access_token` to
`access_token_for_connection`.


### Testing

- [x] This change adds test coverage

- [x] This change has been tested on the latest version of the
platform/language or why not

### Contributor Checklist

- [x] I agree to adhere to the [Auth0 General Contribution
Guidelines](https://github.com/auth0/open-source-template/blob/master/GENERAL-CONTRIBUTING.md).
- [x] I agree to uphold the [Auth0 Code of
Conduct](https://github.com/auth0/open-source-template/blob/master/CODE-OF-CONDUCT.md).

Author: kishore7snehil

auth0/authentication/get_token.py

@@ -278,7 +278,7 @@ def backchannel_login(
             },
         )
 
-    def federated_connection_access_token(
+    def access_token_for_connection(
         self,
         subject_token_type: str, 
         subject_token: str,

auth0/test/authentication/test_get_token.py

@@ -337,10 +337,10 @@ def test_backchannel_login(self, mock_post):
         )
 
     @mock.patch("auth0.rest.RestClient.post")
-    def test_federated_login(self, mock_post):
+    def test_connection_login(self, mock_post):
         g = GetToken("my.domain.com", "cid", client_secret="csec")
 
-        g.federated_connection_access_token(
+        g.access_token_for_connection(
             grant_type="urn:auth0:params:oauth:grant-type:token-exchange:federated-connection-access-token",
             subject_token_type="urn:ietf:params:oauth:token-type:refresh_token",
             subject_token="refid",