Fix error when looking handle with surrounding spaces (#18225)

app/controllers/api/v1/accounts/lookup_controller.rb

@@ -12,5 +12,7 @@ class Api::V1::Accounts::LookupController < Api::BaseController
 
   def set_account
     @account = ResolveAccountService.new.call(params[:acct], skip_webfinger: true) || raise(ActiveRecord::RecordNotFound)
+  rescue Addressable::URI::InvalidURIError
+    raise(ActiveRecord::RecordNotFound)
   end
 end

app/services/resolve_account_service.rb

@@ -66,7 +66,7 @@ class ResolveAccountService < BaseService
       @username = @account.username
       @domain   = @account.domain
     else
-      @username, @domain = uri.split('@')
+      @username, @domain = uri.strip.gsub(/\A@/, '').split('@')
     end
 
     @domain = begin