Update text for SecureFlag Integration

Text update

• Go to the left hand navigation and click Secure
• Under Secure click Security configuration
• In the main screen, click on the Vulnerability Management tab
• Read the subtext for the SecureFlag Integration

The word virtualised should be virtualized (note the z instead of an s).

Reason why

For both product text content and documentation, we use US English as the standard for spelling and grammar.

Implementation Plan

1. Create a DB migration to update the description of SecureFlag initially created in https://gitlab.com/gitlab-org/gitlab/-/blob/master/db/post_migrate/20230328030101_add_secureflag_training_provider.rb
2. Update https://gitlab.com/gitlab-org/gitlab/-/blob/2b283e55292174b29aa44fc77aedec4dac5c4da4/lib/gitlab/database_importers/security/training_providers/importer.rb#L26-26 as well

Verification Steps