[XLA][NFC] Make interface of module loaders consistent.

LoadModuleFromData has (data, format, config, ...) signature while FromFile has (path, config, format, ...). Change the latter so `format` becomes the second argument in both cases.

Since I'm touching this file:
* Use `std::string_view` and `absl::Status`
* Change `ovr_config` parameter to `const &`

PiperOrigin-RevId: 601304308

examples/jax_cpp/main.cc

@@ -58,8 +58,9 @@ int main(int argc, char** argv) {
   std::function<void(xla::HloModuleConfig*)> config_modifier_hook =
       [](xla::HloModuleConfig* config) { config->set_seed(42); };
   std::unique_ptr<xla::HloModule> test_module =
-      LoadModuleFromFile(hlo_filename, xla::hlo_module_loader_details::Config(),
-                         "txt", config_modifier_hook)
+      LoadModuleFromFile(hlo_filename, /*format=*/"txt",
+                         xla::hlo_module_loader_details::Config(),
+                         config_modifier_hook)
           .value();
   const xla::HloModuleProto test_module_proto = test_module->ToProto();