m2a related-items display don't using default collection template by default

Describe the Bug

When related-items display is selected as display for m2a relation, and template field leaved blank, it would be nice if the default collection template will be used.

I also suggest to add extra option in template dropdown of related-items display options: Item (Default display).
With this feature we'll able to set up template like "Blabla {{default_display}}", which will be converted to corresponding template for each collection.

It can look like this

![image](



To Reproduce

Create an m2a relation with related-items display and leave template blank.

Errors Shown

_No response_

What version of Directus are you using?

9.20.4

What version of Node.js are you using?

v17.9.0

What database are you using?

MySQL

What browser are you using?

Chrome

How are you deploying Directus?

locally