feat: Add theme options to select Telescope themes (#710)

* feat: Add theme options to select Telescope themes

Added theme options to the M.pick function to allow selection of
dropdown, ivy, and cursor themes.

* refactor: remove theme argument and integrate into opts

Simplified code by removing the theme argument and integrating it into opts.

* fix: correct default theme settings

Fixed to apply the default theme when opts and opts.theme are not set.

Author: Kohei-Wada

lua/CopilotChat/integrations/telescope.lua

@@ -19,7 +19,11 @@ function M.pick(pick_actions, opts)
   end
 
   utils.return_to_normal_mode()
-  opts = themes.get_dropdown(opts or {})
+
+  if not (opts and opts.theme) then
+    opts = themes.get_dropdown(opts or {})
+  end
+
   pickers
     .new(opts, {
       prompt_title = pick_actions.prompt,