Changed default role for new users (#48)

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- [ ] Has associated issue:
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- [ ] Changes UI
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superset/config.py

@@ -346,7 +346,7 @@ def _try_json_readsha(filepath: str, length: int) -> str | None:
 
 # Authentication Configuration
 AUTH_USER_REGISTRATION = True
-AUTH_USER_REGISTRATION_ROLE = "sql_lab"
+AUTH_USER_REGISTRATION_ROLE = "Alpha"
 AUTH_ROLES_SYNC_AT_LOGIN = True
 AUTH_ROLES_MAPPING = {
     "studio_admin": ["Admin"],