Drop the repeated client_id check in the WPCC guard

[darkdi]

Proposed changes

• Remove the repeated empty( $wpcc_options['client_id'] ) operand from the WPCC activation guard.
• Preserve the guard's current behavior for empty options, a missing or empty client_id, and a present client_id.
• Add the required Jetpack changelog entry (patch, fixed).

If the third operand was intended to check another key, client_secret is the obvious candidate, but this repository only reads wpcc_options; I did not change behavior without evidence.

Related product discussion/links

• No issue or product discussion; found while reading the guard.

Does this pull request change what data or activity we track or use?

No. It removes a duplicate boolean operand and does not change data collection, storage, transmission, or behavior.

Testing instructions

1. Check out this branch.
2. Run php -l projects/plugins/jetpack/class.jetpack.php.
3. Review the guard in Jetpack::handle_deprecated_modules() and confirm its result is unchanged for:
   • empty wpcc_options;
   • a missing or empty client_id;
   • a present, non-empty client_id.

The removed operand was identical to the preceding one, so the boolean expression has the same truth table before and after the change.

[github-actions]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

• ✅ Include a description of your PR changes.
  
• ✅ Add testing instructions.
  
• ✅ Specify whether this PR includes any changes to data or privacy.
  
• ✅ Add changelog entries to affected projects
  

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Jetpack plugin:

The Jetpack plugin has different release cadences depending on the platform:

• WordPress.com Simple releases happen as soon as you deploy your changes after merging this PR (PCYsg-Jjm-p2).
• WoA releases happen weekly.
• Releases to self-hosted sites happen monthly:
  • Scheduled release: October 6, 2026

If you have any questions about the release process, please ask in the #jetpack-releases channel on Slack.

[darkdi]

The bot added Needs Author Reply when the PR was opened, but its checklist is all green and nobody asked anything yet, so I think it's waiting on review rather than on me. The changelog entry is in