Add @typescript-eslint/no-unnecessary-condition rule

https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-unnecessary-condition.md

index.js

@@ -221,6 +221,7 @@ module.exports = {
 				allowDestructuring: true
 			}
 		],
+		'@typescript-eslint/no-unnecessary-condition': 'error',
 		'@typescript-eslint/no-unnecessary-qualifier': 'error',
 		'@typescript-eslint/no-unnecessary-type-arguments': 'error',
 		'@typescript-eslint/no-unnecessary-type-assertion': 'error',