Fix mistake in previous commit

Fix error in b4100ed377

`seq_retiming_evaluate()` returns range from 0 to 1, to which framerate
correction was applied. this is incorrect, and correction should be
applied to function input.

source/blender/sequencer/intern/strip_retiming.cc

@@ -144,8 +144,7 @@ float seq_retiming_evaluate(const Scene *scene, const Sequence *seq, const int f
   const float segment_fac = segment_frame_index / float(segment_length);
 
   const float target_diff = next_handle->retiming_factor - previous_handle->retiming_factor;
-  return previous_handle->retiming_factor +
-         (target_diff * segment_fac) * seq_time_media_playback_rate_factor_get(scene, seq);
+  return previous_handle->retiming_factor + (target_diff * segment_fac);
 }
 
 SeqRetimingHandle *SEQ_retiming_add_handle(Scene *scene, Sequence *seq, const int timeline_frame)

source/blender/sequencer/intern/strip_time.c

@@ -86,13 +86,12 @@ float seq_give_frame_index(const Scene *scene, Sequence *seq, float timeline_fra
 
   frame_index = max_ff(frame_index, 0);
 
+  frame_index *= seq_time_media_playback_rate_factor_get(scene, seq);
+
   if (SEQ_retiming_is_active(seq)) {
     const float retiming_factor = seq_retiming_evaluate(scene, seq, frame_index);
     frame_index = retiming_factor * (length - 1);
   }
-  else {
-    frame_index *= seq_time_media_playback_rate_factor_get(scene, seq);
-  }
 
   /* Clamp frame index to strip content frame range. */
   frame_index = clamp_f(frame_index, 0, length);