Improve handling of non-UTF-8 encoded files in validator

[bleonar5]

Description

The validator currently throws errors when it encounters non-UTF-8 encoded files. This behavior interrupts the validation process and prevents the user from receiving a complete report of all issues with their dataset. Additionally, the validator is checking the encoding of all files, including those that are not directly relevant to the psych-DS schema.

Current Behavior

• The validator throws an error and stops processing when it encounters a non-UTF-8 encoded file.
• All files in the dataset are being checked for UTF-8 encoding, regardless of their relevance to the psych-DS schema.

Desired Behavior

• When encountering a non-UTF-8 encoded file, the validator should:
  • Handle the error gracefully without interrupting the overall validation process.
  • Add an issue to the validation output indicating that the file is not UTF-8 encoded.
• The validator should only check the encoding of relevant files:
  • Canonical datafiles (e.g., CSV files specified in the dataset's metadata).
  • JSON metadata files.
  • Other file types specified as required by the psych-DS schema.