Require URL contains valid protocol in MDM settings end user migration form

[gillespi314]

Issue #18566

[gillespi314]

@RachelElysia, I think the issue found by QAWolf may stem from the changes made to frontend URL validation in this PR. The options for the new validator library are a bit confusing, but looking into the source, it seems that require_protocol must be set in order to check that a protocol is actually present. The protocols and require_valid_protocol only test validity of the protocol prefix if one is detected. Otherwise it considers "example.com" to be ok.

I haven't checked whether the issue might also be present on other pages. In the interest of time, I just imported the new validator library directly on this page so that I could set the additional options required for the validator to check for the presence of a protocol.

Since you are more familiar with the changes more generally, would you mind taking a look at the usage in other places to confirm it works as expected?

[roperzh]

I wonder if there are any other places in the UI that need the protocol explicitly defined?