Fix: Custom Properties named identical to existing properties fails to key

When inserting keys in the viewport by pressing `I`,
certain custom properties would not get keyed if their name
was identical to existing properties (for example `scale`).

That was because we use the name of the property to resolve
an rna path and check if the path resolved. This was of course
true in the described case and the square brackets would never be added.
The solution is to check for `RNA_property_is_runtime` which is false
for properties defined inside Blender.

Pull Request: https://projects.blender.org/blender/blender/pulls/135304

source/blender/animrig/intern/anim_rna.cc

@@ -155,7 +155,10 @@ Vector<RNAPath> get_keyable_id_property_paths(const PointerRNA &ptr)
      * Those need to be animated through an RNA path without the brackets. */
     bool is_resolved = RNA_path_resolve_property(
         &ptr, path.c_str(), &resolved_ptr, &resolved_prop);
-    if (!is_resolved) {
+    /* ID properties can be named the same as internal properties, for example `scale`. In that
+     * case they would resolve, but it wouldn't be the correct property. `RNA_property_is_runtime`
+     * catches that case. */
+    if (!is_resolved || !RNA_property_is_runtime(resolved_prop)) {
       char name_escaped[MAX_IDPROP_NAME * 2];
       BLI_str_escape(name_escaped, id_prop->name, sizeof(name_escaped));
       path = fmt::format("[\"{}\"]", name_escaped);