Fix #122777: The keyframe_insert method throws python exceptions

Just for the `pyrna_struct_keyframe_insert()` function, reduce the
reporting level of keyframe insertion failures from `RPT_ERROR` to
`RPT_WARNING`. This prevents the conversion of these reports to a Python
exception.

`CombinedKeyingResult::generate_reports()` now accepts an option
argument `report_level`, so that the caller is in control over the type
of reports it generates.

Previously only errors were converted to exceptions; warnings were
implicitly cleared and never displayed. To avoid these 'keyframe
insertion failure' reports from becoming invisible, the
`pyrna_struct_keyframe_insert()` function now sends any warnings to
stdout (unless there were errors, in which case the old
error-to-exception behaviour is still there).

Pull Request: https://projects.blender.org/blender/blender/pulls/122827

source/blender/python/intern/bpy_rna_anim.cc

@@ -415,16 +415,26 @@ PyObject *pyrna_struct_keyframe_insert(BPy_StructRNA *self, PyObject *args, PyOb
                                                            eInsertKeyFlags(options));
     const int success_count = combined_result.get_count(SingleKeyingResult::SUCCESS);
     if (success_count == 0) {
-      combined_result.generate_reports(&reports);
+      /* Ideally this would use the GUI presentation of RPT_ERROR, as the resulting pop-up has more
+       * vertical space than the single-line warning in the status bar. However, semantically these
+       * may not be errors at all, as skipping the keying of certain properties due to the 'only
+       * insert available' flag is not an error.
+       *
+       * Furthermore, using RPT_ERROR here would cause this function to raise a Python exception,
+       * rather than returning a boolean. */
+      combined_result.generate_reports(&reports, RPT_WARNING);
     }
     result = success_count != 0;
   }
 
   MEM_freeN((void *)path_full);
 
-  if (BPy_reports_to_error(&reports, PyExc_RuntimeError, true) == -1) {
+  if (BPy_reports_to_error(&reports, PyExc_RuntimeError, false) == -1) {
+    BKE_reports_free(&reports);
     return nullptr;
   }
+  BPy_reports_write_stdout(&reports, nullptr);
+  BKE_reports_free(&reports);
 
   if (result) {
     WM_event_add_notifier(C, NC_ANIMATION | ND_ANIMCHAN | NA_EDITED, nullptr);