Fix issue with expanding

emacs-lsp/dap-mode#316

Author: yyoncho

lsp-treemacs.el

@@ -1102,7 +1102,7 @@
       (setq-local face-remapping-alist '((button . default)))
       (lsp-treemacs--set-mode-line-format search-buffer title)
       (lsp-treemacs-generic-refresh)
-      (lsp-treemacs--expand 'LSP-Generic expand-depth)
+      (when expand-depth (lsp-treemacs--expand 'LSP-Generic expand-depth))
       (current-buffer))))
 
 (defalias 'lsp-treemacs--show-references 'lsp-treemacs-render)