FIX initialize all_dates_dict in user feature prelaunch test

When writing this test I only used S2 data for which data_container does not use all_dates_dict.

In manage_s1_raw_data however, self.all_dates is used.

This commit does not fix external features compatibility with sentinel 1 data because an other error emerges, but I'll open a new issue for this one and write tests to fix this behavior.

related to #508 (closed)
fix #515 (closed)