Do not expose direct editing if no master key is available

[juliushaertl]

This will make sure that direct editing is only exposed to mobile clients then a master key is available in case server side encryption is used.

I would propose to backport this even though the public interface is extended, but it is only used by the files app.

cc @camilasan @tobiasKaminsky @marinofaggiana for the clients:
I would expect there should be no changes required from the client side since it would just return an empty list of direct editors then.

Fixes nextcloud/ios#1340

[ChristophWurst]

👍 🐘

[rullzer]

Yes smart move

[faily-bot]

🤖 beep boop beep 🤖

Here are the logs for the failed build:

Status of 32530: failure

mariadb10.1-php7.2

Show full log

There were 2 warnings:

1) Test\Files\ViewTest::testRenameFailDeleteTargetKeepSource
Trying to configure method "writeStream" which cannot be configured because it does not exist, has not been specified, is final, or is static

2) Test\Files\ViewTest::testCopyFailDeleteTargetKeepSource
Trying to configure method "writeStream" which cannot be configured because it does not exist, has not been specified, is final, or is static

--

There was 1 failure:

1) Test\Files\Cache\Wrapper\CacheJailTest::testWithoutNormalizer
Failed asserting that 0 is greater than 0.

/drone/src/tests/lib/Files/Cache/CacheTest.php:554

mysql8.0-php7.2

• cancelled - typically means that the tests took longer than the drone CI allows them to run