Always honor CLAP main thread requirement

If this ever becomes a bottleneck we can always decide to not do it
right there and then.

src/plugin/bridges/clap.cpp

@@ -88,12 +88,16 @@ ClapPluginBridge::ClapPluginBridge(const ghc::filesystem::path& plugin_path)
                             const auto& [plugin_proxy, _] =
                                 get_proxy(request.owner_instance_id);
 
-                            // We'll ignore the main thread requirement for
-                            // simple lookup functions like this for
-                            // performance's sake
-                            return plugin_proxy.extensions_.audio_ports
-                                ->is_rescan_flag_supported(plugin_proxy.host_,
-                                                           request.flag);
+                            return plugin_proxy
+                                .run_on_main_thread(
+                                    [&, host = plugin_proxy.host_,
+                                     audio_ports = plugin_proxy.extensions_
+                                                       .audio_ports]() {
+                                        return audio_ports
+                                            ->is_rescan_flag_supported(
+                                                host, request.flag);
+                                    })
+                                .get();
                         },
                 [&](const clap::ext::audio_ports::host::Rescan& request)
                     -> clap::ext::audio_ports::host::Rescan::Response {