refactor(nvim): cleanup flatten_table_to_string

Author: Zhe Yu

lua/vectorcode/integrations/codecompanion/common.lua

@@ -16,18 +16,21 @@ return {
     if type(t) == "string" then
       return t
     end
-    
+
     -- Handle empty tables or tables with empty strings
-    local flattened = vim.iter(t):flatten(math.huge):totable()
-    local non_empty = vim.iter(flattened):filter(function(item)
-      return type(item) == "string" and vim.trim(item) ~= ""
-    end):totable()
-    
-    if #non_empty == 0 then
+    local flattened = vim
+      .iter(t)
+      :flatten(math.huge)
+      :filter(function(item)
+        return type(item) == "string" and vim.trim(item) ~= ""
+      end)
+      :totable()
+
+    if #flattened == 0 then
       return "Unknown error occurred"
     end
-    
-    return table.concat(non_empty, "\n")
+
+    return table.concat(flattened, "\n")
   end,
 
   ---@param use_lsp boolean