Fix get top billionaires BROKEN file

[CaedenPH]

Describe your change:

Fixes a get_top_billionaires and unmarks it as disabled

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
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• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

[CaedenPH]

@cclauss This pr also fixes a broken file. The problem was that the unix timestamps were negative (if the billionaire is older than 53) which python causes python datetime to error (overflow error)

[tianyizheng02]

Could we change the doctests so that we don't have to update the ages every year? (see previous comment)

[tianyizheng02]

Tried it locally, looks like it works 👍