Inconsistent Dutch number formatting in Dutch test cases

There are inconsistencies in the Dutch number formatting in the test cases located at ovos_date_parser/res/nl-nl/date_time_test.json. This issue was identified in PR #1: https://github.com/OpenVoiceOS/ovos-date-parser/pull/1

Discussion: https://github.com/OpenVoiceOS/ovos-date-parser/pull/1#discussion_r1831942323

The codebase shows that the correct Dutch format for compound numbers (21-99) is without spaces, joining the numbers with "en". This is evidenced by date_time.json which uses the correct format: "eenentwintig", "tweeentwintig", etc.

The test cases need to be updated for consistency:

• "twee en negentig" → "tweeennegentig"
• "vier en vijftig" → "vierenvijftig"
• "zes en veertig" → "zesenveertig"
• "acht en tachtig" → "achtentachtig"
• "een en twintig" → "eenentwintig"
• "een en dertig" → "eenendertig"
• "twee en dertig" → "tweeendertig"
• "twee en vijftig" → "tweeenvijftig"

The suggestion about missing edge cases (year 0, negative years, large years) remains valid, but the primary formatting inconsistency needs to be addressed first.

Requester: @JarbasAl.