Apply mask to events_meta as we initially draw events from all data…

…sets and `signal_event_post_sampling_processing` expects same shape `events_meta` and `events` arrays.

It follows the same logic as in the initial signal events drawing in L886-897.

skyllh/core/signal_generator.py

@@ -699,7 +699,8 @@ def _draw_valid_sig_events_for_dataset_and_shg(
             )
             m = (events_meta['ds_idx'] == ds_idx) &\
                 (events_meta['shg_idx'] == shg_idx)
-            events = mc[events_meta['ev_idx'][m]]
+            events_meta = events_meta[m]
+            events = mc[events_meta['ev_idx']]
             if len(events) > 0:
                 events = shg.sig_gen_method.\
                     signal_event_post_sampling_processing(