fix: escape backslash when processing component's css (#11425)

The `.w-\[100px\]` selector is a valid CSS class. However, when processed by the tools package, it is incorrectly saved as `.w-[100px]`, making it an invalid selector.  
With this PR, when a backslash is encountered during processing inside a CSS file, it is properly escaped before being saved to the new file.

Fixes: #11413

Author: nnaydenow

packages/tools/lib/css-processors/css-processor-components.mjs

@@ -22,7 +22,8 @@ let customPlugin = {
         build.onEnd(result => {
             result.outputFiles.forEach(async f => {
                 // scoping
-                const newText = scopeVariables(f.text, packageJSON);
+                let newText = scopeVariables(f.text, packageJSON);
+                newText = newText.replaceAll(/\\/g, "\\\\"); // Escape backslashes as they might appear in css rules
                 await mkdir(path.dirname(f.path), {recursive: true});
                 writeFile(f.path, newText);