DOC: Remove unused image rotator

The use of the rotator was dropped in matplotlib#26332. Currently, it causes an
exception on every page, because there is no 'image_rotator' element,
but this is only visible in the console or, if you have the inspector
open, it'll start the debugger.

Author: QuLogic

doc/_static/image-rotator.js

@@ -785,5 +785,4 @@ def setup(app):
         bld_type = 'rel'
     app.add_config_value('skip_sub_dirs', 0, '')
     app.add_config_value('releaselevel', bld_type, 'env')
-    app.add_js_file('image-rotator.js')
     app.connect('html-page-context', add_html_cache_busting, priority=1000)