MICROBA-1011 | Remove duplicate allowlist entries and add constraint preventing future occurrences

A "section" tag in an OLX upload used to map to the
SemanticSectionDescriptor, which translated it into a Sequence
("sequential" tag). This is both obscure and confusing, since it uses
language that predates Studio. Back in the LMS prototype days,
"section" was inconsistently used to be interchangeable with "sequence"
and "sequential", and what Studio today calls a "section" was called a
"chapter". Bits of this legacy terminology are still around in the
courseware rendering code.

The upshot is that if you make an OLX tag "section" before this commit,
it would not map to what we call a "Section" in all our documentation,
but to a "Subsection"; furthermore, if that <section> only had one child
element, the node would be replaced with its singular child, removing
the <section> node from the course tree entirely.

The fact that you can make a "section" OLX tag
at all is nowhere in our documentation because courses haven't been
written that way since late 2011 or early 2012.

SemanticSectionDescriptor came up as part of the XModule ->
XBlock conversion efforts as a legacy XModule that isn't worth
converting. With the removal of this class, all XBlocks
in edx-platform are "pure" XBlocks, ending our reliance
on the XModule-to-XBlock shimming infrastructure.

This commit also removes the process_includes decorator, which was only
used for "section" tags. This does NOT delete the ProblemBlock-specific
<include> tag, which is still supported (if obscure).

There is a chance that through tribal knowledge or copy-paste, some
section tags survive in the wild of old edX courses. It's difficult for
us to assess because by its nature, this tag doesn't just say
"section", but instead actually does the mutation on import so it's
stored as "sequential" in the modulestore–therefore things like
CourseGraph can't detect it.
The fix for any such XML-authored courses is:
* For instances of <section> that wrap a single child node,
  replace the <section> node in favor of its child node.
* For instances of <section> that wrap a sequence of children,
  substitute <section> with <sequential>
Note that "<section>" is a valid HTML tag
type and so may show up in any component that can contain HTML and is
unrelated to the course structure OLX tag alias "<section>" that this
commit removes.

DEPR-124

disable xsslint

* fix: six was being used without being imported

Removed usage of the python library six from module. This is fixing an error where the python library six is used in a module without being imported. Multiple PRs merging around same time caused this conflict.

replace six with str

MICROBA-1011 | Remove duplicate allowlist entries and add constraint to model to prevent future occurrences

[MICROBA-1011]
- Add data migration to remove the duplicate certificate allowlist entries before adding the new constraint to the CertificateWhitelist model.
- Add `unique_together` constraint to the CertificateWhitelist model. A learner should only have a single allowlist entry per course-run.

Added custom for SSO auth entries to monitor which auth entries are
still in use.

AA-213: create progress tab mfe waffle flag

The Learning MFE had a bug where instructors selecting
'View As: Audit' would find themselves redirected to the
'Enroll Now' page. This was because the Courseware API,
 which powers the MFE, checked courseware access *after*
setting up masquerading--so, instead of checking whether
the instructor had access to view the course, we checked
whether some arbitrary un-enrolled learner would have
access to the course (the answer is generally No).

We fix this by doing what the Legacy courseware index
does: calculate courseware access *before* setting up
masquerading.

TNL-7989

feat: update to edx-ace 1.0.0

The new version switches how you specify recipients, to use
lms_user_id instead of usernames.

AA-489

[BD-04] Create CustomTagTemplateBlock, convert TranslateCustomTagDescriptor to XBlock and remove RawDescriptor

pyupgrade in enterprise_support

BOM-2375-student-part2

upgraded course_date_signals & course_groups apps.

pyupgrade in enterprise-support.

AA-671: Course Home MFE Progress Tab API cleanup

[TSD] add annotations for AUTOMATIC_AUTH_FOR_TESTING feature flag

In https://github.com/edx/edx-platform/pull/25955 `HiddenDescriptor`
(which was a subclass of `RawDescriptor` with a custom `student_view()`)
was converted to an XBlock. It is used as the `default_class` by the
`CachingDescriptorSystem` classes. However `RawDescriptor` is still
being used by `XMLModuleStore`. This has been replaced by
`HiddenDescriptor` as well.

[TSD] Added annotation for ALLOW_HIDING_DISCUSSION_TAB feature flag