Expose non-generic messages for 403 HTTP status to the end user

[VicDeo]

Description

8b2ebe2#diff-5f714a00dd14764258a4e4a95b600644974f29a1046a61a7cecd40f96337163d

Introduces a regression: all messages that are coming from 3rd-party apps (files_antivirus, firewall, etc) are masked with a generic message for HTTP status 403

Related Issue

https://github.com/owncloud/enterprise/issues/4418
owncloud/files_antivirus#395

Motivation and Context

The real reason why the file hasn't been uploaded is misreported

How Has This Been Tested?

1. Enable and set files_antivirus
2. Upload EICAR

Expected

Web UI reports that file is infected with EICAR

Actual

Web UI reports that user has no upload permission

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

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

[phil-davis]

LGTM