Uploading an old method chunked file with checksum should fail using new DAV path

This scenario is failing in CI:
```
Scenario: Uploading an old method chunked file with checksum should fail using new DAV path # /drone/src/tmp/testrunner/tests/acceptance/features/apiMain/checksums.feature:263
Given using new DAV path # FeatureContext::usingOldOrNewDavPath()
When user "Alice" uploads chunk file "1" of "3" with "AAAAA" to "/myChecksumFile.txt" with checksum "MD5:45a72715acdd5019c5be30bdbb75233e" using the WebDAV API # ChecksumContext::userUploadsChunkFileOfWithToWithChecksum()
Then the HTTP status code should be "503" # FeatureContext::thenTheHTTPStatusCodeShouldBe()
HTTP status code 206 is not the expected value 503
Failed asserting that 206 matches expected '503'.
And user "Alice" should not see the following elements # FeatureContext::userShouldSeeTheElements()
| /myChecksumFile.txt |
```

"old chunked upload to the old DAV endpoint" is supported and working.
"new chunked upload to the onew DAV endpoint" is not supported and we don't test it any more.

"old chunked upload to the new DAV endpoint" looks like it will work on OCIS and reva. It fails on oC10 - oC10 gives a 503 response. Maybe it is just an accidental default behavior that it looks like it will work on OCIS and reva.

Firstly we need to decide if it is OK for it to "work by accidental default".

Then we can decide if we need to adjust the test suite, or?