vlsub: fixes creation of cache directory if it doesn't exist

When VLSub asks for the cache directory and it doesn't exist an error is
thrown. This patch makes sure that the directory is created before it is
accessed for writing.

Fixes #21595
Signed-off-by: Thomas Guillem <thomas@gllm.fr>

(cherry picked from commit 583dded749fb3078a8cad495efcd5f4bcef0a875)
Signed-off-by: Pierre Ynard <linkfanel@yahoo.fr>

Author: blurrrb

share/lua/extensions/VLSub.lua

@@ -1488,6 +1488,22 @@ function download_subtitles()
 
   subfileName = subfileName.."."..item.SubFormat
   local tmp_dir = vlc.config.cachedir()
+  -- create the cache directory if it doesn't already exist
+  local separator = ""
+  local current_dir = ""
+  if package.config:sub(1, 1):match("/") then
+    -- unix based systems
+    separator = "/"
+    current_dir = "/"
+  else
+    -- windows systems
+    separator = "\\"
+  end
+  for dir in tmp_dir:gmatch("[^"..separator.."]+") do
+    current_dir = current_dir..dir..separator
+    local vars = vlc.io.mkdir(current_dir, "0700")
+  end
+
   local file_target_access = true
 
   local tmpFileName = dump_zip(