fix(fzf): decouple defaults from opts to easy switch profiles (#4190)

## Description
This decouples `defaults` from `opts`, so that if users switch to
another profile they can take advantage of
the profile's default settings and prompts.

I use `default-title` either way. I just stumbled upon this when I tried
the rest profiles and thought maybe there
would be users who would prefer to have the default prompts if they
chose another profile.
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  why we should accept this pull request. -->

## Related Issue(s)
No
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  If this PR fixes any issues, please link to the issue here.
  - Fixes #<issue_number>
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## Screenshots

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## Checklist

- [x] I've read the
[CONTRIBUTING](https://github.com/LazyVim/LazyVim/blob/main/CONTRIBUTING.md)
guidelines.

---------

Co-authored-by: Folke Lemaitre <folke.lemaitre@gmail.com>

lua/lazyvim/plugins/extras/editor/fzf.lua

@@ -74,18 +74,6 @@ return {
       config.defaults.actions.files["alt-c"] = config.defaults.actions.files["ctrl-r"]
       config.set_action_helpstr(config.defaults.actions.files["ctrl-r"], "toggle-root-dir")
 
-      -- use the same prompt for all
-      local defaults = require("fzf-lua.profiles.default-title")
-      local function fix(t)
-        t.prompt = t.prompt ~= nil and " " or nil
-        for _, v in pairs(t) do
-          if type(v) == "table" then
-            fix(v)
-          end
-        end
-      end
-      fix(defaults)
-
       local img_previewer ---@type string[]?
       for _, v in ipairs({
         { cmd = "ueberzug", args = {} },
@@ -98,7 +86,8 @@ return {
         end
       end
 
-      return vim.tbl_deep_extend("force", defaults, {
+      return {
+        "default-title",
         fzf_colors = true,
         fzf_opts = {
           ["--no-scrollbar"] = true,
@@ -186,9 +175,24 @@ return {
             previewer = vim.fn.executable("delta") == 1 and "codeaction_native" or nil,
           },
         },
-      })
+      }
     end,
     config = function(_, opts)
+      if opts[1] == "default-title" then
+        -- use the same prompt for all pickers for profile `default-title` and
+        -- profiles that use `default-title` as base profile
+        local function fix(t)
+          t.prompt = t.prompt ~= nil and " " or nil
+          for _, v in pairs(t) do
+            if type(v) == "table" then
+              fix(v)
+            end
+          end
+          return t
+        end
+        opts = vim.tbl_deep_extend("force", fix(require("fzf-lua.profiles.default-title")), opts)
+        opts[1] = nil
+      end
       require("fzf-lua").setup(opts)
     end,
     init = function()