infra: enable no-unneeded-ternary eslint rule (#3257)

Author: qwerty541

.eslintrc.json

@@ -203,7 +203,7 @@
         // "no-ternary": "off",
         // "no-trailing-spaces": "warn",
         // "no-underscore-dangle": "warn",
-        // "no-unneeded-ternary": "warn",
+        "no-unneeded-ternary": "warn",
         // "object-curly-spacing": [ "warn", "always" ],
         // "one-var": "off",
         // "operator-assignment": [ "warn", "never" ],