[Backport] CSV file upload error within the CMS

Issue Description:

Since BrXM 14.7.3, customers are no longer able to upload CSV files to assets within the CMS. When doing so, they receive the error message as shown in the attached screenshot. This issue only occurs when attempting to upload on Windows, while the same files can be uploaded without issue on Linux.

Workaround:

Adding property "extension.mimetype.allowed.mappings" with value ".csv,text/csv" resolves the issue, so customer is using this in the short term.

Expectation:

File upload validation for csv files should behave as it did prior to Bloomreach version 14.7.3.