obs-studio: resolve failed wrapping if a plugin has no data path
obs-studio: resolve failed wrapping if a plugin has no data path

fixes a regression due to #186548 where the symlinkJoin fails when a
package does not have that path such as `obs-studio-plugins.wlrobs`

Only one `symlinkJoin` is necessary

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs