Updated compute_features, compute_labels & compute_rate to address bug #507

[jonasmeltzer]

To address the issue of missing data causing errors in the compute_features and compute_labels functions, this pull request introduces additions to help handle such scenarios.

Some of the changes we made include:

• Adding test cases to reproduce the issue (in the test_vaep file)
• Updating the compute_features and compute_labels functions by adding try except statements to handle the error
• Handling the bug scenario downstream in the compute_rate function

Our code passes all initial test cases as well as the additional cases we wrote. Thanks in advance for taking a look, and let us know if you have any questions.