fix: improve looks_like_json function

Co-authored-by: Marco Pereirinha <pereirinha@users.noreply.github.com>

Author: epigeyre

php/class-utils.php

@@ -543,7 +543,21 @@ public static function pathinfo( $path, $flags = 15 ) {
 	 * @return bool
 	 */
 	public static function looks_like_json( $thing ) {
-		return is_string( $thing ) && ! empty( ltrim( $thing ) ) && in_array( $thing[0], array( '{', '[' ), true );
+		if ( ! is_string( $thing ) ) {
+			return false;
+		}
+
+		$thing = trim( $thing );
+	
+		if ( empty( $thing ) ) {
+			return false;
+		}
+	
+		if ( ! in_array( $thing[0], array( '{', '[' ), true ) ) {
+			return false;
+		}
+
+		return true;
 	}
 
 	/**