LV2 Client: Avoid declaring the turtle_recall feature in plugin manifests

This is an implementation detail for the build system of the plugin.
Users of the plugin should not know or care that this extension is
available.

modules/juce_audio_plugin_client/LV2/juce_LV2_Client.cpp

@@ -1111,7 +1111,6 @@ private:
               "\tlv2:optionalFeature\n"
               "\t\tlv2:hardRTCapable ;\n"
               "\tlv2:extensionData\n"
-              "\t\t<" JUCE_TURTLE_RECALL_URI "> ,\n"
               "\t\tstate:interface ;\n"
               "\tlv2:requiredFeature\n"
               "\t\turid:map ,\n"