Remove progress bar types

introduced in 0552ffeeda but never referenced

src/pip/_internal/utils/ui.py

@@ -8,10 +8,7 @@ import time
 from signal import SIGINT, default_int_handler, signal
 
 from pip._vendor import six
-from pip._vendor.progress.bar import (
-    Bar, ChargingBar, FillingCirclesBar, FillingSquaresBar, IncrementalBar,
-    ShadyBar,
-)
+from pip._vendor.progress.bar import Bar, FillingCirclesBar, IncrementalBar
 from pip._vendor.progress.helpers import HIDE_CURSOR, SHOW_CURSOR, WritelnMixin
 from pip._vendor.progress.spinner import Spinner
 
@@ -216,20 +213,6 @@ class DownloadIncrementalBar(BaseDownloadProgressBar,  # type: ignore
     pass
 
 
-class DownloadChargingBar(BaseDownloadProgressBar,  # type: ignore
-                          ChargingBar):
-    pass
-
-
-class DownloadShadyBar(BaseDownloadProgressBar, ShadyBar):  # type: ignore
-    pass
-
-
-class DownloadFillingSquaresBar(BaseDownloadProgressBar,  # type: ignore
-                                FillingSquaresBar):
-    pass
-
-
 class DownloadFillingCirclesBar(BaseDownloadProgressBar,  # type: ignore
                                 FillingCirclesBar):
     pass