feat: allow data.azuread_application lookup using identifier_uri

[JonasBak]

This PR introduces a small feature to the azuread_application data source that allows us to get the application based on an identifying URI. This is a feature we would really like to use. It looks like this:

data "azuread_application" "example" {
  identifier_uris  = [
    "api://example-app",
  ]
}

I've implemented it in a way where you can provide a list of one element to the identifier_uris field, instead of introducing another field called identifier_uri that is just a string, as I thought it might be easy to mix up the two fields, but would love some input on this. I added an error if more than one element is provided in identifier_uris.

[manicminer]

Hi @JonasBak, thanks for this contribution, this would be a useful addition to the data source! Apologies for the delayed review.

If we are going to match any one identifier URI, then I think it would be better to add a new property identifier_uri and leave the existing identifier_uris as a computed attribute. My thinking here is that the returned application could have >1 identifier URI, which we would be saving to state, and this would create a discrepency between configuration and state. There is possibly no consequence to this at the moment, but this may throw an error in future versions of the provider RPC protocol (which is how the provider communicates with Terraform).

If you could rework this to add this additional property whilst keeping the existing attribute as-is, then I think this should be good to merge. The remainder of the implementation looks good to me.

Apologies again for the tardiness of this review. If you aren't in a position to make this change, just let me know and I'll happily pick this up whilst preserving your original commits.

Thanks!

[JonasBak]

Thanks for the review @manicminer, I rebased and added your suggestion 👍
It now looks like this:

data "azuread_application" "test" {
  identifier_uri = "api://example-app"
}

[manicminer]

Thanks for updating @JonasBak, this LGTM! 👍

[manicminer]

Test results