Delete unused config option and help page

[VicDeo]

Description

Follow up on remove Help section from settings #34612

Related Issue

• Fixes What to do about settings/help #36381

Motivation and Context

Remove orphaned files and unused config option for the route that is no longer available

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Database schema changes (next release will require increase of minor version instead of patch)
• Breaking change (fix or feature that would cause existing functionality to change)
• Technical debt
• Tests only (no source changes)

Checklist:

• Code changes
• Unit tests added
• Acceptance tests added
• Documentation ticket raised:
• Changelog item, see TEMPLATE

[codecov]

Codecov Report

Merging #37225 into master will decrease coverage by 10.73%.
The diff coverage is n/a.

@@              Coverage Diff              @@
##             master   #37225       +/-   ##
=============================================
- Coverage     64.87%   54.14%   -10.74%     
=============================================
  Files          1269       63     -1206     
  Lines         74948     7510    -67438     
  Branches       1331     1331               
=============================================
- Hits          48626     4066    -44560     
+ Misses        25930     3052    -22878     
  Partials        392      392

Flag	Coverage Δ	Complexity Δ
#javascript	54.14% <ø> (ø)	0 <ø> (ø)	⬇️
#phpunit	?	?

Impacted Files	Coverage Δ	Complexity Δ
apps/updatenotification/templates/admin.php
lib/private/Encryption/Keys/Storage.php
lib/private/App/CodeChecker/NodeVisitor.php
lib/private/RedisFactory.php
apps/dav/lib/Avatars/AvatarNode.php
...s/dav/appinfo/Migrations/Version20170202213905.php
apps/dav/lib/Upload/ChunkLocationProvider.php
apps/files/lib/AppInfo/Application.php
apps/systemtags/list.php
apps/files_external/lib/Lib/Backend/DAV.php
... and 1194 more

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