Member Content: Register Login Form Block and Shortcode

[n7studios]

Summary

Adds this feature request by providing options to embed the Member Content login form using a block or shortcode:

Testing

• PageBlockMemberContentLoginCest: Test the block can be added to a Page, viewed and login works
• PageShortcodeMemberContentLoginCest: Test the shortcode can be added to a Page, viewed and login works

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)