Fix: Always show vonDatum and bisDatum in fetch URL for analog inputs chart

- Ensure local date state is never empty by falling back to default date if Redux is empty
- Prevent missing date values in fetch URL after multiple dropdown or button interactions
- Improves reliability of

.env.production

@@ -5,5 +5,5 @@ NEXT_PUBLIC_CPL_API_PATH=/CPL
 NEXT_PUBLIC_EXPORT_STATIC=true
 NEXT_PUBLIC_USE_CGI=true
 # App-Versionsnummer
-NEXT_PUBLIC_APP_VERSION=1.6.629
+NEXT_PUBLIC_APP_VERSION=1.6.630
 NEXT_PUBLIC_CPL_MODE=production