multi: support verbose conncache closure handle

- Change closure handle to receive verbose setting from the easy handle
  most recently added via curl_multi_add_handle.

The closure handle is a special easy handle used for closing cached
connections. It receives limited settings from the easy handle most
recently added to the multi handle. Prior to this change that did not
include verbose which was a problem because on connection shutdown
verbose mode was not acknowledged.

Ref: https://github.com/curl/curl/pull/3598

Co-authored-by: Daniel Stenberg

Closes https://github.com/curl/curl/pull/3618