fix: mark files with only whitespace as not found

lib/sync-settings.js

@@ -577,7 +577,7 @@ module.exports = {
 	async fileContent (filePath) {
 		try {
 			const content = await readFile(filePath, { encoding: 'utf8' })
-			return content !== '' ? content : null
+			return content.trim() !== '' ? content : null
 		} catch (err) {
 			console.error(`Error reading file ${filePath}. Probably doesn't exist.`, err)
 			return null