Fix bug for issue number 3319 (Required files client side validation)

[JSeifBY]

when adding a new post with a required field type 'File'; if i let the file empty the form is submitted and generate an error 'empty file' but the problem that the post has been added to the list without a file.

bug fix : iterate over pods required 'file' field type test if at least one file is selected, if not prevent submit and alert message showing 'You have same empty required files!'

Changelog:

• Show required message for file fields that are required.

[sc0ttkclark]

I like what you're doing here, but we need a couple more tweaks to the text shown and I'd like to make the messaging / alert a little less alert(), maybe showing a message at the top of the screen <div id="message" class="error">....</div> or something like that, as well as messages and/or red markings on individual fields.

[JSeifBY]

Sorry for that response delay,
i have just removed the alert dialog and added an inline error messages. I was thinking about adding notification manager like https://notifyjs.com/ to notify user of occurred errors (not only for required files), for example in long scroll pages we can't find the errors in a short time.

[sc0ttkclark]

@JSeifBY can you provide collaborator access to your repository?

[JSeifBY]

Done!

[sc0ttkclark]

After some changes, it looks better. We need to update some of the JS here though to make sure the markup is right for 2.7

@pglewis can you check the logic of this out and confirm if markup it's using to add/remove the message is correct? Feel free to suggest changes that would be better overall for per-field validation messages.

[sc0ttkclark]

@JSeifBY can you add access for @JoryHogeveen to your repo?

[JoryHogeveen]

Tests are failing, other than that it's a go from me!

The base branch was changed.