Bug fix: reflect WINLEN for DA window length in the yaml files

[yuanxue2870]

Before the bugfix, the variable WINLEN was set in the settings_DA_test. The window length in the yaml file was hard coded as 'PT24H', being a 24-hr DA length.

With the bugfix, the variable WINLEN was still set in the settings_DA_test. The window length in the yaml file can take varied WINLEN as configured in the settings.