Fixes #4313

Summary:

This PR modifies the validateMethod function in the _command-loader.js file to enhance error messages by displaying the file paths of both the original and conflicting command definitions when a duplicate command is detected. This change makes it easier to debug and track the source of duplicate commands.

Example Error Message:

When a duplicate command is found, the error message will now look like this:

Error while loading the API commands: the command testNamespace.testCommand() is already defined.
- First defined in: /path/to/firstFile.js
- Current file: /path/to/secondFile.js