Bugzilla

### Description

I noticed recently that curly braces are not being enforced by ESLint in tree. 

I used `git bisect` and I believe that Bug 1920531 regressed this behavior. 

### Steps to reproduce

1) Create a test file `example.js` in the root of the `mozilla-unified` tree.
```js
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

let x = 0;
if (x === 0) true;
```
---

2) Run `./mach eslint --fix example.js`

---

**Expected Behavior**
✖ 0 problems (0 errors, 0 warnings, 2 fixed)
```js
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

let x = 0;
if (x === 0) {
  true;
}
```

**Actual Behavior**
✖ 0 problems (0 errors, 0 warnings, 0 fixed)

---

3) Run `./mach eslint --fix example.js --rule "curly:error"`.
The file is fixed as expected when manually adding `--rule "curly:error"`.

### Description

I noticed recently that curly braces are not being enforced by ESLint in tree. 

I used `git bisect` and I believe that Bug 1920531 regressed this behavior. 

### Steps to reproduce

1) Create a test file `example.js` in the root of the `mozilla-unified` tree.
```js
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

let x = 0;
if (x === 0) true;
```
---

2) Run `./mach eslint --fix example.js`

---

**Expected Behavior**
✖ 0 problems (0 errors, 0 warnings, 2 fixed)
```diff
--- a/before
+++ b/after
@@ -3,5 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

 let x = 0;
-if (x === 0) true;
+if (x === 0) {
+  true;
+}
```

**Actual Behavior**
✖ 0 problems (0 errors, 0 warnings, 0 fixed)

---

3) Run `./mach eslint --fix example.js --rule "curly:error"`.
The file is fixed as expected when manually adding `--rule "curly:error"`.