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