[n7studios]

Summary

update_broadcast() and update_sequence_email() sent a default for a parameter even when it wasn't specified, overwriting the existing value:

• update_broadcast() always sent public: false, so updating any field of a public broadcast made it non-public. public is now only sent when specified.
• update_sequence_email() always sent send_days: null, which resets the email to the sequence's schedule, so updating any field removed the email's own send days. send_days is now only sent when specified; pass an empty array to reset.

Testing

• testUpdatePublicBroadcastWithoutPublic: Test updating a public broadcast's subject keeps it public, with the same dates.
• testUpdateSequenceEmailSendDays: Test updating a sequence email's subject keeps its send days, and an empty array resets them.

Checklist

• I have written a test and included it in this PR
• I have run all tests and they pass
• The code passes when running the PHP CodeSniffer
• Code meets WordPress Coding Standards for PHP, HTML, CSS and JS
• Security and Sanitization requirements have been followed
• I have assigned a reviewer or two to review this PR (if you're not sure who to assign, we can do this step for you)