fix(fs): error when escaping out of add and add_directory

[figsoda]

When pressing a into escape in neo-tree, I ran into this error, this fixes the issue for me

Error executing vim.schedule lua callback: ...eovimPackages/start/neo-tree.nvim/lua/neo-tree/utils.lua:833: attempt to index local 's' (a nil value)
stack traceback:
	...eovimPackages/start/neo-tree.nvim/lua/neo-tree/utils.lua:833: in function 'brace_expand_split'
	...eovimPackages/start/neo-tree.nvim/lua/neo-tree/utils.lua:951: in function 'brace_expand'
	....nvim/lua/neo-tree/sources/filesystem/lib/fs_actions.lua:329: in function 'on_confirm'
	...eovimPackages/start/dressing.nvim/lua/dressing/input.lua:108: in function ''
	vim/_editor.lua: in function ''
	vim/_editor.lua: in function <vim/_editor.lua:0>