fix: check existing_client support workspaceFolder (#3452)

if existing_client does not support workpaceFolder
should spawn a new server instance

lua/lspconfig/manager.lua

@@ -58,12 +58,10 @@ end
 --- @param root_dir string
 --- @param client vim.lsp.Client
 function M:_notify_workspace_folder_added(root_dir, client)
-  if is_dir_in_workspace_folders(client, root_dir) then
-    return
-  end
-
-  local supported = vim.tbl_get(client, 'server_capabilities', 'workspace', 'workspaceFolders', 'supported')
-  if not supported then
+  if
+    is_dir_in_workspace_folders(client, root_dir)
+    or not vim.tbl_get(client, 'server_capabilities', 'workspace', 'workspaceFolders', 'supported')
+  then
     return
   end
 
@@ -132,6 +130,10 @@ function M:_start_client(bufnr, new_config, root_dir, single_file, silent)
     bufnr = bufnr,
     silent = silent,
     reuse_client = function(existing_client)
+      if not vim.tbl_get(existing_client, 'server_capabilities', 'workspace', 'workspaceFolders', 'supported') then
+        return false
+      end
+
       if (self._clients[root_dir] or {})[existing_client.name] then
         self:_notify_workspace_folder_added(root_dir, existing_client)
         return true