Hide author for closed plugins

[dd32]

Permanently closed plugins continue to show the Author of plugins that are removed. While I appreciate the plugin-now-closed placeholder, I question the need to keep the Authorship & Developer details public.

For example, I've just closed a test plugin of mine: ​https://wordpress.org/plugins/test-plugin-4/

The plugin continues to show

• By Me! in the header
• dd32 under the Contributors & Developers header with the “Test Plugin 4” is open source software. The following people have contributed to this plugin. text.

I propose we remove these two pieces of data.
This also aids in how we handle plugins whose owners have requested data anonymization as this will remove the empty (or "anonymous 12345") texts.

[Ipstenu]

We're just talking perma-closes? I'm 100% okay with that :)

[dd32]

Yes Perma-closes, which I guess in some places is considered closed for more than x days? I don't actually know the logic for it off the top of my head.

If it's temporary, yeah they can stay.

[Ipstenu]

Perma Close: If closed by author request or if there are no committers

Everything is is not listed as permanent, but after 60 days we tell you (vaguely) why (security, guidelines, etc).

[dd32]

In 13728:

Plugin Directory: Hide the author byline when a plugin is closed permanently.

Fixes #5496.