unify password|null snowflake auth method typing

Author: jankuca

src/platform/notebooks/deepnote/integrationTypes.ts

@@ -95,12 +95,7 @@ interface BaseSnowflakeConfig extends BaseIntegrationConfig {
 export type SnowflakeIntegrationConfig = BaseSnowflakeConfig &
     (
         | {
-              authMethod: null;
-              username: string;
-              password: string;
-          }
-        | {
-              authMethod: typeof SnowflakeAuthMethods.PASSWORD;
+              authMethod: typeof SnowflakeAuthMethods.PASSWORD | null;
               username: string;
               password: string;
           }