[QA] Part files are not considered for quota while they are uploaded

Seen while testing https://github.com/owncloud/core/pull/39895 with 10.11.0-beta.1

The initial description for this PR has
"

• Part files will also be considered for quota while they're being
  uploaded
  "

I believe this part of the PR was not implemented:

User2 has 40 MB quota. He has 5.4 MB already, and is uploading a 33 MB file (with chunks of 10 MB).
The used quota remains at 5.4 MB until the very last moment, when the file is assembled.

Similarly, when the uploading a 9.5 MB file (no chunking, directly into the target directory with a *.part file) the quota does not see the *.part file. Only after assembly, it jumps up.

Expected behaviour:

• Quota used also counts part files and chunks.

Everything else in https://github.com/owncloud/core/pull/39895 seems to work fine.