enhance(emoji): update to Unicode 17, unify and lazy-load emoji data (#39363)

Generate emoji data from Unicode 17's `emoji-test.txt`, keeping existing
aliases. `public/assets/emoji.json` is now the single emoji data file,
also loaded by the backend. Rendered emoji drop their `aria-label`, the
dark theme inverts key on a new `data-alias` attribute instead.

Skin tone variants and their Gitea-only aliases are removed, GitHub has
none either.

Emoji autocompletion is now lazy-loaded with the markdown editor,
shrinking the index JS chunk from 653KB to 563KB.

---------

Signed-off-by: silverwind <me@silverwind.io>
Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: bircni <bircni@icloud.com>

modules/markup/main_test.go

@@ -12,7 +12,7 @@ import (
 )
 
 func TestMain(m *testing.M) {
-	setting.IsInTesting = true
+	setting.SetupGiteaTestEnv()
 	markup.RenderBehaviorForTesting.DisableAdditionalAttributes = true
 	markup.RefreshFileNamePatterns()
 	os.Exit(m.Run())