fix: nil access exception with git integration when changing branches (#2774)

Fix nil access exception appearing when changing branches

Author: jacobkania

lua/nvim-tree/explorer/node.lua

@@ -29,7 +29,7 @@ end
 ---@param absolute_path string
 ---@return GitStatus
 local function get_git_status(parent_ignored, status, absolute_path)
-  local file_status = parent_ignored and "!!" or status.files and status.files[absolute_path]
+  local file_status = parent_ignored and "!!" or (status and status.files and status.files[absolute_path])
   return { file = file_status }
 end