Fixed report/block user hidden for valid WordPress.com authors

[annaharri89]

Description

Fixes #21144

• The isSelfHosted check used ‘authorBlogId’ (author's site ID) which is -1 for authors without their own site but didn’t account for self-hosted Jetpack blogs connected to WordPress.com. I replaced isSelfHosted with ‘authorId > 0’ to match what the report/block actions actually require, which is that the user has a word press account. These options should only be hidden for external RSS feeds and self hosted sites without Jetpack.
• Removed the now-unused isSelfHosted() from ReaderUtils and its wrapper.
• Updated the tests to reflect these changes.

Testing instructions

1. Check out the trunk branch and find a post that hides the report/block user
2. Confirm that post is not an external RSS feed or a self hosted site without Jetpack (the user who posted it has a wordpress account)
3. Check out my branch and view the same post. Validate the report/block user now shows.

Before my fix:

After my fix:

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[jkmassel]

Thanks for the contribution @annaharri89!

Reviewing this, I'm still not sure it's the correct approach – I think all we need to do here is check that the user is currently logged into WordPress.com in order to show that button – if they are, they should be able to block a feed, site, or user that way.

Happy to re-review or discuss further!

[annaharri89]

@jkmassel I thought you need the id of the user you want to report or block. Even if the current user is signed in to wordpress, that doesn't guarantee a post's author has a wordpress account does it? Or am I misunderstanding?

(hasWordPressAccount is about the post's author not the signed in user)