[FIX] web: /web/binary/upload

Doesn't seem used since it's been broken forever on python 3:
base64.b64encode returns binary data, on which json.dumps chokes.

Still, removing the endpoint on old stables seems a bit brutal so just
fix it.

closes odoo/odoo#56650

X-original-commit: 7fc9bc28986d69184df5a4fdeefbe09e4b39b8f0
Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>

addons/web/controllers/main.py

@@ -1544,7 +1544,7 @@ class Binary(http.Controller):
         try:
             data = ufile.read()
             args = [len(data), ufile.filename,
-                    ufile.content_type, base64.b64encode(data)]
+                    ufile.content_type, pycompat.to_text(base64.b64encode(data))]
         except Exception as e:
             args = [False, str(e)]
         return out % (json.dumps(callback), json.dumps(args)) if callback else json.dumps(args)