remove unwanted autosession plugin

lua/custom/plugins/autosession.lua

@@ -1,9 +0,0 @@
--- Plugin to automatically create and restore simple sessions
-return {
-  'rmagatti/auto-session',
-  config = function()
-    require('auto-session').setup {
-      auto_session_enable_last_session = true,
-    }
-  end,
-}