Close http connection in perform method of Request class (#6889)

HTTP connections must be explicitly closed in many cases, and letting
perform method close connections makes its callers less redundant and
prevent them from forgetting to close connections.

app/services/resolve_account_service.rb

@@ -179,11 +179,10 @@ class ResolveAccountService < BaseService
   def atom_body
     return @atom_body if defined?(@atom_body)
 
-    response = Request.new(:get, atom_url).perform
-
-    raise Mastodon::UnexpectedResponseError, response unless response.code == 200
-
-    @atom_body = response.to_s
+    @atom_body = Request.new(:get, atom_url).perform do |response|
+      raise Mastodon::UnexpectedResponseError, response unless response.code == 200
+      response.to_s
+    end
   end
 
   def actor_json