feat: add help text for katana metadata

[Srishti-Gupta74]

Description

Added help text for the user-facing field in plugins/katana/metadata.json to improve clarity when configuring the plugin.

Changes made:

• Added help text for the Target URL field.
• Refreshed the plugin checksum after updating the metadata.

Related Issues

Closes #526

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

How Has This Been Tested?

• Ran:

  python scripts/refresh_plugin_checksum.py --plugin katana

• Verified the metadata changes and checksum update using:

  git diff

Checklist

• My code follows the code style of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.