Databricks hook: fix expiration time check (#20036)

There was a logical error in the check of expiration time that could
lead to authentication failures when executing long-running jobs

airflow/providers/databricks/hooks/databricks.py

@@ -176,7 +176,7 @@ def _get_aad_token(self, resource: str) -> str:
         if resource in self.aad_tokens:
             d = self.aad_tokens[resource]
             now = int(time.time())
-            if d['expires_on'] > (now - TOKEN_REFRESH_LEAD_TIME):  # it expires in more than 5 minutes
+            if d['expires_on'] > (now + TOKEN_REFRESH_LEAD_TIME):  # it expires in more than 2 minutes
                 return d['token']
             self.log.info("Existing AAD token is expired, or going to expire soon. Refreshing...")