Fix #144332: VSE solo preview does not work

`render_give_ibuf_direct()` just called `seq_render_strip()`, which
tried to get image from intra frame cache. This always succeeded,
because the intra frame cache does not accept timeline frame argument.

Using intra frame cache here is incorrect. Source cache must be used.
If source cache lookup fails, intra frame cache must be invalidated
before calling `seq_render_strip()`.

Pull Request: https://projects.blender.org/blender/blender/pulls/144396

source/blender/sequencer/intern/render.cc

@@ -2047,6 +2047,8 @@ ImBuf *render_give_ibuf_direct(const RenderData *context, float timeline_frame,
 {
   SeqRenderState state;
 
+  intra_frame_cache_set_cur_frame(
+      context->scene, timeline_frame, context->view_id, context->rectx, context->recty);
   ImBuf *ibuf = seq_render_strip(context, &state, strip, timeline_frame);
   return ibuf;
 }