message: Use `Result` return value in index init FFI function
diff: @@ -136,15 +136,17 @@ ocaml_export! {
  rt,
  configuration: OCamlRef<TezosContextTezEdgeStorageConfiguration>,
  patch_context: OCamlRef<Option<PatchContextFunction>>,
  - ) -> OCaml<DynBox<TezedgeIndexFFI>> {
  + ) -> OCaml<Result<DynBox<TezedgeIndexFFI>, String>> {
  let patch_context = rt.get(patch_context).to_option().map(BoxRoot::new);
  let configuration: TezosContextTezEdgeStorageConfiguration = configuration.to_rust(rt);
  - // TODO - TE-261: remove this unwrap, and return Result on this function.
  - let index = initialize_tezedge_index(&configuration, patch_context).unwrap();
  + let result = initialize_tezedge_index(&configuration, patch_context)
  + .map_err(|err| format!("{:?}", err));
  - set_context_index(&index);
  + if let Ok(index) = &result {
  + set_context_index(index);
  + }
  - OCaml::box_value(rt, index.into())
  + result.map(|index| OCaml::box_value(rt, index.into()).root()).to_ocaml(rt)
  }
  fn tezedge_index_close(
  