Bleach 6 update (#4610)

* Update bleach requirement from ==5.0.* to ==6.2.*

Updates the requirements on [bleach](https://github.com/mozilla/bleach) to permit the latest version.
- [Changelog](https://github.com/mozilla/bleach/blob/main/CHANGES)
- [Commits](https://github.com/mozilla/bleach/compare/v5.0.0...v6.2.0)

---
updated-dependencies:
- dependency-name: bleach
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

* Update bleach parameter types

* Fix tests

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/pretix/base/invoice.py

@@ -289,7 +289,7 @@ class BaseReportlabInvoiceRenderer(BaseInvoiceRenderer):
     def _clean_text(self, text, tags=None):
         return self._normalize(bleach.clean(
             text,
-            tags=tags or []
+            tags=set(tags) if tags else set()
         ).strip().replace('<br>', '<br />').replace('\n', '<br />\n'))
 
 
@@ -461,7 +461,7 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
     def _draw_event(self, canvas):
         def shorten(txt):
             txt = str(txt)
-            txt = bleach.clean(txt, tags=[]).strip()
+            txt = bleach.clean(txt, tags=set()).strip()
             p = Paragraph(self._normalize(txt.strip().replace('\n', '<br />\n')), style=self.stylesheet['Normal'])
             p_size = p.wrap(self.event_width, self.event_height)