fix(gitsigns): use silent for gitsigns keymaps (#5841)

## Description

When executing `<leader>ghs`, the command line window will flicker.
Therefore, it should be run silently.

## Related Issue(s)
None

## Screenshots

<!-- Add screenshots of the changes if applicable. -->

## Checklist

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

lua/lazyvim/plugins/editor.lua

@@ -153,7 +153,7 @@ return {
         local gs = package.loaded.gitsigns
 
         local function map(mode, l, r, desc)
-          vim.keymap.set(mode, l, r, { buffer = buffer, desc = desc })
+          vim.keymap.set(mode, l, r, { buffer = buffer, desc = desc, silent = true })
         end
 
         -- stylua: ignore start