fix missing encoding in CssSelector.php

CSS Selector expressions are not properly encoded, for example
input[type="password"]
is a perfectly valid CSS selector, and
$page->mouse()->find('input[type="password"]')
should have worked, but it generate a javascript syntax error at runtime:
```
document.querySelectorAll("input[name="email"]").length
```
resulting in
PHP Fatal error:  Uncaught HeadlessChromium\Exception\ElementNotFoundException: The search for "document.querySelectorAll("input[name="email"]").length" returned no result. in /home/hans/projects/tryparrotai-unofficial-api/vendor/chrome-php/chrome/src/Input/Mouse.php:302
Stack trace:
#0 /home/hans/projects/tryparrotai-unofficial-api/vendor/chrome-php/chrome/src/Input/Mouse.php(269): HeadlessChromium\Input\Mouse->findElement()


Exactly the same issue as #576

Author: divinity76

src/Dom/Selector/CssSelector.php

@@ -19,11 +19,32 @@ public function __construct(string $expression)
 
     public function expressionCount(): string
     {
-        return \sprintf('document.querySelectorAll("%s").length', $this->expression);
+        $encodedExpr = \json_encode(
+            $this->expression,
+            \JSON_UNESCAPED_SLASHES
+                | \JSON_UNESCAPED_UNICODE
+                | \JSON_THROW_ON_ERROR
+        );
+
+        return \sprintf(
+            'document.querySelectorAll(%s).length',
+            $encodedExpr
+        );
     }
 
     public function expressionFindOne(int $position): string
     {
-        return \sprintf('document.querySelectorAll("%s")[%d]', $this->expression, $position - 1);
+        $encodedExpr = \json_encode(
+            $this->expression,
+            \JSON_UNESCAPED_SLASHES
+                | \JSON_UNESCAPED_UNICODE
+                | \JSON_THROW_ON_ERROR
+        );
+
+        return \sprintf(
+            'document.querySelectorAll(%s)[%d]',
+            $encodedExpr,
+            $position - 1
+        );
     }
 }