Update LanguageDropdown and Header components for improved localization and layout

- Enhanced the LanguageDropdown component by updating language names to their native forms and adding non-breaking spaces for better readability.
- Refactored the Header component to improve layout, including a gap between icons and adjusted class attributes for better spacing.
- Ensured consistent filtering of navigation links and improved accessibility for the contact link.

src/components/LanguageDropdown.astro

@@ -11,10 +11,10 @@ const { currentLang } = Astro.props;
 type SupportedLanguage = (typeof supportedLanguages)[number];
 
 const languages = [
-  { code: 'en' as SupportedLanguage, name: 'English', flag: 'gb' },
-  { code: 'nl' as SupportedLanguage, name: 'Dutch', flag: 'nl' },
-  { code: 'de' as SupportedLanguage, name: 'German', flag: 'de' },
-  { code: 'fr' as SupportedLanguage, name: 'French', flag: 'fr' },
+  { code: 'en' as SupportedLanguage, name: 'English\u00A0\u00A0', flag: 'gb' },
+  { code: 'nl' as SupportedLanguage, name: 'Nederlands', flag: 'nl' },
+  { code: 'de' as SupportedLanguage, name: 'Deutsch', flag: 'de' },
+  { code: 'fr' as SupportedLanguage, name: 'Français', flag: 'fr' },
 ].filter((lang) => supportedLanguages.includes(lang.code));
 
 const currentLanguage = languages.find((lang) => lang.code === currentLang) || languages[0];