fix: resolve null request content on export & header example import issue

[leochen800]

Fixes

• Fixed an issue where the request content became null when exporting records.
• Fixed an issue where the example values in headers were not correctly populated during import.
• Fixed an issue where POST and PUT requests could not be sent properly.
• Added -UseBasicParsing to all request calls to avoid permission and compatibility issues in certain environments.

Tests

• Verified that request content is properly preserved after export.
• Verified that header example values are correctly displayed after import.
• Verified that POST and PUT requests can be sent successfully.
• Verified that requests execute correctly in restricted environments.