feat(icons): add manga-dex (#1402)

Co-authored-by: Dashboard Icons Manager <193821040+dashboard-icons-manager[bot]@users.noreply.github.com>

tree.json

@@ -1079,6 +1079,7 @@
         "mak.png",
         "makemkv.png",
         "maloja.png",
+        "manga-dex.png",
         "mango.png",
         "manjaro-linux.png",
         "mantisbt.png",
@@ -3140,6 +3141,7 @@
         "mailpit.svg",
         "mainsail.svg",
         "maintainerr.svg",
+        "manga-dex.svg",
         "manjaro-linux.svg",
         "manyfold.svg",
         "maptiler.svg",
@@ -5159,6 +5161,7 @@
         "mak.webp",
         "makemkv.webp",
         "maloja.webp",
+        "manga-dex.webp",
         "mango.webp",
         "manjaro-linux.webp",
         "mantisbt.webp",