Add provider protocol compatibility UI err msg during registry discovery

[findkim]

[update] a few followup PRs #19977 #19981 related to this feature

The changes add a UI error during provider discovery with the registry to suggest to users to update constraints with the closest provider version with compatible plugin protocol.

Output of init on TF config with provider null version constraint 1.0.0 and plugin protocol 5

provider "null" {
  version = "1.0.0"
}

Output of init on TF config with provider null version constraint 3.0.0-pre and plugin protocol 5

provider "null" {
  version = "3.0.0-pre"
}

Local registry test setup with provider null with versions and varying protocol ranges

{
  "id": "terraform-providers/null",
  "verified": true,
  "versions": [
    ...
    {
      "version": "1.0.0",
      "protocols": ["4"],
      "platforms": [{"os": "darwin", "arch": "amd64"}]
    },
    {
      "version": "2.0.0-alpha",
      "protocols": ["4", "5.0"],
      "platforms": [{"os": "darwin", "arch": "amd64"}]
    },
    {
      "version": "3.0.0-pre",
      "protocols": ["6.0"],
      "platforms": [{"os": "darwin", "arch": "amd64"}
      ]
    }
  ]
}

[apparentlymart]

LGTM!

I left a note inline about filtering prerelease versions but I'm happy to get this merged and then work on that as a separate changeset if you'd like.

We also talked out-of-band about the exact rendering of the error messages; happy also to iterate on that in subsequent commits, since it's not a hard blocker for release.

[apparentlymart]

One thing I noticed in your screenshots in the PR is that it proposed an alpha build as the "earliest version" supporting protocol 5. This makes me think we should filter out prereleases from consideration here since the suggestion in the error message (using ~> 2.0) can't actually match prerelease versions... prereleases are only selected if they are specified exactly.

Philosophically too, I think we want to avoid ever promoting the use of prereleases outside of a release notes context where we can give more information about the expectations for the release.

[findkim]

great catch & point! I'll merge and iterate on the how pre-releases are handled to never be suggested by Terraform.

[findkim]

Follow-up PR for posterity #19977

[ghost]

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