[CT-3377] [Regression] dbt deps fails on tarball dependencies

[imre-kerr-sb1]

Is this a regression in a recent version of dbt-core?

• I believe this is a regression in dbt-core functionality
• I have searched the existing issues, and I could not find an existing issue for this regression

Current Behavior

When dependencies.yml includes a tarball dependency, I get an error message from dbt deps:

11:18:06  Running with dbt=1.7.1
11:18:06  Updating lock file in file path: /workspace/dbt-deps-tarball-failure/asdf/package-lock.yml
11:18:06  Encountered an error:
Runtime Error
  The packages.yml file in this project is malformed. Please double check
  the contents of this file and fix any errors before retrying.
  
  You can find more information on the syntax for this file here:
  https://docs.getdbt.com/docs/package-management
  
  Validator Error:
  dbt_utils was not found in the package index. Packages on the index require a namespace, e.g dbt-labs/dbt_utils

Expected/Previous Behavior

Expected output:

11:27:03  Running with dbt=1.6.8
11:27:03  Installing dbt_utils
11:27:03  Installed from tarball (url: https://codeload.github.com/dbt-labs/dbt-utils/tar.gz/0.9.6)

The validator should

• not check the index for tarball dependencies
• not validate the namespace/package-name for tarball dependencies
• mention the correct filename (this is a minor thing)

Steps To Reproduce

1. In a new dbt project
2. With the following dependencies.yml:

packages:
  - tarball: https://codeload.github.com/dbt-labs/dbt-utils/tar.gz/0.9.6
    name: 'dbt_utils'

3. Run dbt deps
4. See error message above

Relevant log output

No response

Environment

- OS: Ubuntu 22.04.3
- Python: 3.11.1
- dbt-core (latest working version): 1.6.8
- dbt-core (earliest regression version): 1.7.0
- dbt-core (latest version): 1.7.1

Which database adapter are you using with dbt?

No response

Additional Context

No response