[Bug] dbt hangs when packages have empty values

[emmyoop]

Is this a new bug in dbt-core?

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

Current Behavior

When a package is defined as

packages:
    - local: ""  

Running dbt deps results in dbt hanging.

Expected Behavior

Get an error that the value is am empty string

Steps To Reproduce

Define a packages.yml in a dbt project as

packages:
- local: ""

run `dbt deps`

### Relevant log output

_No response_

### Environment

```markdown
- OS:
- Python:
- dbt:

Which database adapter are you using with dbt?

No response

Additional Context

No response