minor #1049 [Site] Fix CodeExpander without expandCodeButton target (…

…smnandre)

This PR was merged into the 2.x branch.

Discussion
----------

[Site] Fix CodeExpander without expandCodeButton target

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| License       | MIT

The CodeBlock component uses the "code-expander" Stimulus controller, which is responsible to... expand the code.

But on the [LazyImage](https://ux.symfony.com/lazy-image) page, the button usually present is replaced by an informational div.

| Common usage | LazyImage page |
| - | - |
| ![with-button](https://github.com/symfony/ux/assets/1359581/b960d8b0-5250-4ac9-b6ac-061f602b4123) | ![without-button](https://github.com/symfony/ux/assets/1359581/7d74b931-7a1b-4185-a879-be8872d0b291) |

Hence the following JS error

```console
Error connecting controller

 Error: Missing target element "expandCodeButton" for "code-expander" controller
    get stimulus.js:2153
    connect code-expander-controller-402db0232698738a8988bbaba08c533d.js:1
   [...]
    start stimulus.js:1974
    startStimulusApp loader-e1ee9ace0562f2e6a52301e4ccc8627d.js:2
    <anonymous> bootstrap-9ce723d68588a7672b3759b7a06e85c3.js:1

Object { identifier: "code-expander", controller: {…}, element: div.terminal-body }
stimulus.js:2017:20
```

I propose to make the code-expander controller work even when the button is not connected, thus allowing to decouple the "expand" action from its origin.

Commits
-------

9e7f7c1 Fix CodeExpander without expandCodeButton target

ux.symfony.com/assets/controllers/code-expander-controller.js

@@ -4,7 +4,7 @@ export default class extends Controller {
     static targets = ['useStatements', 'expandCodeButton', 'codeContent'];
 
     connect() {
-        if (this.#isOverflowing(this.codeContentTarget)) {
+        if (this.hasExpandCodeButtonTarget && this.#isOverflowing(this.codeContentTarget)) {
             this.expandCodeButtonTarget.style.display = 'block';
             // add extra padding so the button doesn't block the code
             this.codeContentTarget.classList.add('pb-5');
@@ -18,8 +18,10 @@ export default class extends Controller {
 
     expandCode(event) {
         this.codeContentTarget.style.height = 'auto';
-        this.codeContentTarget.classList.remove('pb-5');
-        this.expandCodeButtonTarget.remove();
+        if (this.hasExpandCodeButtonTarget) {
+            this.expandCodeButtonTarget.remove();
+            this.codeContentTarget.classList.remove('pb-5');
+        }
     }
 
     #isOverflowing(element) {