Fix export of corporate author to MSOffice

[Siedlerchr]

Fix tests
Fix #4329

The underlying problem is the same as in #4152
However, I came up with a workaround for MSOffice.

1. Getting the original field
2. Check for corporate author (braces start and end)
3. get latex free value
4. Readd braces for corporate
5. Parse author

The only edgecase which can occur if the entry starts with an author in latex braces and ends with an author in latex braces. That one will probably be interpreted as corporate.

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• Change in CHANGELOG.md described
• Tests created for changes
• Manually tested changed features in running JabRef
• Screenshots added in PR description (for bigger UI changes)
• Ensured that the git commit message is a good one
• Check documentation status (Issue created for outdated help page at help.jabref.org?)

[tobiasdiez]

Well, that solution is clearly a hack but one that works (in simple situations). It would be way better to include corporation parsing to the author parser. The Office export is not the only situation where we need this information (e.g. main table display). But since a proper solution requires substantial refactoring (e.g. introduction of Person and Corporation deriving from Author), I'm fine with merging this PR. But please add a TODO comment explaining that this is an ugly workaround...

[Siedlerchr]

The author parser is not the problem, as long as the braces are present corporate authors are detected and correctly recognized.

it's the latex to Unicode converter who kills the braces from corporate authors. This is the core problem. See other linked issue.
And I currently see no easy way to either distinguish latex macros and corporate braces.