[tests-only] add tests demonstrating issue-product-203 in shareWithUsers scenarios

[individual-it]

Description

1. make sharing with user tests demonstrate and work despite file_target in share response product#203
2. adjust one test, so it does not fail because of When a share exists its impossible to share a renamed folder ocis#719 (in that test the renaming is not essential to the test, and the test does not check the renaming)
3. small improvement is error output

Related Issue

part of owncloud/ocis#518

Motivation and Context

1. make tests work to avoid further regressions
2. have tests that demonstrate the current behaviour

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)
• Breaking change (fix or feature that would cause existing functionality to change)
• Technical debt
• Tests

Checklist:

• Code changes
• Unit tests added
• Acceptance tests added
• Documentation ticket raised:

Open tasks:

• ...

[phil-davis]

Rebased - let's see what CI thinks.

[individual-it]

I've added an extra commit to avoid owncloud/ocis#719