Refactor StringUtilTest to use parameterized tests (#14126)

* Parameterize tests (issue #676)

* Remove unnecessary quotes in CSV tests

* Apply IntelliJ auto-format

* Fix indentation in StringUtilTest

* Fix code formatting in StringUtilTest

* Remove csl-styles/locales file

* Use text blocks and fix formatting

* Revert "Remove csl-styles/locales file"

This reverts commit c7dd338.

* Fix format issue in textblock test

* Refactor tests to use text block format

* Fix text block indentation

* Address review comments

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Co-authored-by: Oliver Kopp <[email protected]>

Author: Shanaya-1981