fix: builtin/terraform error while updating OpenTofu

[diofeher]

Resolves #13627

Skips trying to update terraform.io/builtin/terraform, since it's not possible to update it, as it follows the same version of the OpenTofu binary.

Checklist

• I have run the complete test suite to ensure all tests and linters pass.
• I have thoroughly tested my code changes to ensure they work as expected, including adding additional tests for new functionality.
• I have written clear and descriptive commit messages.
• I have provided a detailed description of the changes in the pull request, including the problem it addresses, how it fixes the problem, and any relevant details about the implementation.
• I have ensured that the code is well-documented and easy to understand.

[diofeher]

Hi @JamieMagee, would someone be able to review this one? Thanks!