Parameterize tests in logic.formatter.bibtexfields

[EricW123]

Refs #676

This PR refactors RemoveHyphenatedNewlinesFormatterTest, TrimWhitespaceFormatterTest, UnicodeConverterTest and UnitsToLatexFormatterTest to use parameterized tests (@CsvSource and @valuesource) following the one-assertion-per-test guideline.

Note: My classmates are also contributing to this issue.

@espertusnu

How to test:

./gradlew :jablib:test \
    --tests org.jabref.logic.formatter.bibtexfields.TrimWhitespaceFormatterTest \
    --tests org.jabref.logic.formatter.bibtexfields.UnicodeConverterTest \
    --tests org.jabref.logic.formatter.bibtexfields.UnitsToLatexFormatterTest \
    --tests org.jabref.logic.formatter.bibtexfields.RemoveHyphenatedNewlinesFormatterTest