fix(pay_ios): add privacy manifest for App Store compliance

[stephenmcd]

Adds PrivacyInfo.xcprivacy declaring no tracking, no data collection, and no required-reason API usage, matching the plugin's actual behavior. Wires it into both the CocoaPods podspec (resource bundle) and the Swift Package Manager target so it ships regardless of the integration method used to consume pay_ios.

Fixes #251

⚠️
Hello, and thank you for your contributions!

Please review the following checklist before creating a new pull request:

• Review and contribute to existing pull requests and open issues to avoid redundant efforts.
• Read the contribution guidelines.
• Assign reviewers.
• If applicable, include a reference to related issues.
• If this is a new feature, create an issue and coordinate with other contributors to make sure the feature can be made available in all platforms supported.

⚠️ Delete this block before creating the pull request.

Describe the changes proposed

A clear and concise description of the changes included in this pull request.

Screenshots / Videos

If useful, include any screeshots or screencasts to better explain the change.

Additional context

Add any other context about the change here.