Issue while playing back fair play content (non legacy) in safari

[TcT2k]

The mock encrypted event inside initializeMediaKeys does have null initData.
When getSupportedKeySystem() is called this results in an null is not an object (evaluating 'arrayBuffer2.byteLength') exception.

I think the following line in src/plugin.js line should have it's if condition reversed, so that null init data is correctly handled before calling hasSession() with the nullvalue.

videojs-contrib-eme/src/plugin.js

Line 83 in 8820c09

if (hasSession(sessions, initData) || !initData) {