fix(RHINENG-15180): Fix CSV data export with unicode chars

[kruai]

Overview

This PR is being created to address RHINENG-15180.
Encodes export_service's POST requests in utf-8 and sets the charset header accordingly. Also makes a try/catch more specific so we can more easily detect this kind of error in the future - it used to just broadly catch all Exceptions and handle them the same way, so the UnicodeEncodeError went undetected.

PR Checklist

• Keep PR title short, ideally under 72 characters
• Descriptive comments provided in complex code blocks
• Include raw query examples in the PR description, if adding/modifying SQL query
• Tests: validate optimal/expected output
• Tests: validate exceptions and failure scenarios
• Tests: edge cases
• Recovers or fails gracefully during potential resource outages (e.g. DB, Kafka)
• Uses type hinting, if convenient
• Documentation, if this PR changes the way other services interact with host inventory
• Links to related PRs

Secure Coding Practices Documentation Reference

You can find documentation on this checklist here.

Secure Coding Checklist

• Input Validation
• Output Encoding
• Authentication and Password Management
• Session Management
• Access Control
• Cryptographic Practices
• Error Handling and Logging
• Data Protection
• Communication Security
• System Configuration
• Database Security
• File Management
• Memory Management
• General Coding Practices

[chambridge]

LGTM

[kruai]

/retest

[kruai]

/retest

[fstavela]

/retest