Docs: Fix phpdoc tags for WP Http methods

[Frozzare]

I notice that _get_first_available_transport method in WP_Http has the wrong access value, it's used public but the access tag says private and that _dispatch_request method has static tag but is not used as a static method.

This patch will change the access value for _get_first_available_transport and remove static from _dispatch_request.

[DrewAPicture]

Hi @Frozzare, thanks for the patch! We'll handle the @access change here, and removal of the @static tag in #32246.

[DrewAPicture]

In 36367:

Docs: Update the @access tag value for WP_Http::_get_first_available_transport() from private to public.

When the method was introduced in [17914], the name was underscore-prefixed as is core style for private-use, though it was also introduced with a public access modifier for the declaration. Due to core's committment to backward-compatibility, the access modifier overrules in this case, meaning that while the method is underscore-prefixed and was originally-intentioned to be private, it is and always will be a public method, and the documentation should reflect that.

Props Frozzare.
Fixes #35289.