Eliminate use of `extract()` in `validate_another_blog_signup()`. 

The extracted variables set/overwrite globals. `$user` does not need to be pulled from `validate_blog_form()` as it is not used in this function.

See #22400.

Built from https://develop.svn.wordpress.org/trunk@28445


git-svn-id: http://core.svn.wordpress.org/trunk@28272 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Eliminate use of `extract()` in `validate_user_signup()`. 

`$orig_username` does not need to be pulled from `validate_user_form()` as it is not used in this function.

See #22400.

Built from https://develop.svn.wordpress.org/trunk@28446


git-svn-id: http://core.svn.wordpress.org/trunk@28273 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Eliminate use of `extract()` in `validate_blog_signup()`:

* `$orig_username` does not need to be pulled from `wpmu_validate_user_signup()` as it is not used in this function.
* `$user` does not need to be pulled from `wpmu_validate_blog_signup()` as it is not used in this function.
* For the `wpmu_validate_user_signup()` portion, rename `$result` and `$errors` to $user_result` and `$user_errors` for disambiguation with the blog values below.

See #22400.

Built from https://develop.svn.wordpress.org/trunk@28447


git-svn-id: http://core.svn.wordpress.org/trunk@28274 1a063a9b-81f0-0310-95a4-ce76da25c4cd