Don't allow to select folder in create dialog under media type

[bjarnef]

Prerequisites

• I have added steps to test this contribution in the description below

Description

Under a media type it is possible to select folder option, which fails as it isn't supported (only at root or under other folders/containers).
This is also how it works under document types, where folder option is not shown in create dialog under a document/element type.

I also cherry picked a few other changes from #14833 like some typos.

Before

After

It is still possible to select "Folder" option in create dialog at root level and under other folders/containers - just like it work with document types.

The create dialog isn't really used for member types are the moment since it route directly to edit view, but I aligned it with media type create dialog and we may enable containers for member types as well later in #14833

[github-actions]

Hi there @bjarnef, thank you for this contribution! 👍

While we wait for one of the Core Collaborators team to have a look at your work, we wanted to let you know about that we have a checklist for some of the things we will consider during review:

• It's clear what problem this is solving, there's a connected issue or a description of what the changes do and how to test them
• The automated tests all pass (see "Checks" tab on this PR)
• The level of security for this contribution is the same or improved
• The level of performance for this contribution is the same or improved
• Avoids creating breaking changes; note that behavioral changes might also be perceived as breaking
• If this is a new feature, Umbraco HQ provided guidance on the implementation beforehand
• 💡 The contribution looks original and the contributor is presumably allowed to share it

Don't worry if you got something wrong. We like to think of a pull request as the start of a conversation, we're happy to provide guidance on improving your contribution.

If you realize that you might want to make some changes then you can do that by adding new commits to the branch you created for this work and pushing new commits. They should then automatically show up as updates to this pull request.

Thanks, from your friendly Umbraco GitHub bot 🤖 🙂

[bjarnef]

@nul800sebastiaan I cherry picked these changes from the other PR, but allowing folder/container to be be created under an existing media type doesn't really make sense :)

[mikecp]

Hi @bjarnef ,
Thanks for spotting this and providing a solution 👍

Someone from the team will have a look at it soon!

[emmagarland]

Hi @bjarnef, thanks so much for your pull request to stop allowing a folder to be created under a media type.

I have verified it and it has now been successfully merged! 🙌

Finally, I've marked this PR with the project/bellisima label so that we will remember to revisit this feature for Bellissima as well. You're welcome to have a look at creating an equivalent PR for the new backoffice v14 as well if relevant, but if not then it's a reminder for the HQ team to implement the same functionality before new backoffice gets released.

As always, thanks for your efforts to improve the Umbraco experience!

Emma