Remove vendored tenacity

Author: ichard26

news/10822.vendor.rst

@@ -0,0 +1 @@
+Remove vendored tenacity.

src/pip/_vendor/__init__.py

@@ -110,7 +110,6 @@ def vendored(modulename):
     vendored("rich.style")
     vendored("rich.text")
     vendored("rich.traceback")
-    vendored("tenacity")
     if sys.version_info < (3, 11):
         vendored("tomli")
     vendored("truststore")