Exclude widget gui target test from default build
Exclude widget gui target test from default build

- The nvim-qt-widget executable is used to test the shell widget and
  should not be built by default

ngkaho1234/neovim-qt,ravloony/neovim-qt,equalsraf/neovim-qt,ngkaho1234/neovim-qt,ravloony/neovim-qt,equalsraf/neovim-qt,0x90sled/neovim-qt,0x90sled/neovim-qt,Pireax/neovim-qt,ravloony/neovim-qt,equalsraf/neovim-qt,Pireax/neovim-qt,0x90sled/neovim-qt,equalsraf/neovim-qt,Pireax/neovim-qt,ngkaho1234/neovim-qt