Safari Will No Longer Save Passwords Without Usernames in iOS 15.4

In the iOS 15.4, iPadOS 15.4, and macOS Monterey 12.3 betas, Apple has added a minor quality of life improvement to the way Safari saves passwords. At the current time, Safari will gladly save a password without a username, which can lead to confusion later, but that's no longer the case in the beta updates.
When you are prompted to save a password to iCloud Keychain in iOS 15.4, iPadOS 15.4, or ‌macOS Monterey‌ 12.3 and Safari has only detected a password, Safari will pop up a window