[bug] JSONL Output doesn't always contain a JSON object in the Details key

[xathon]

Describe the bug
The JSONL Output doesn't always contain a JSON object in the Details key. If it's empty, it will contain the string "-". This makes it hard to parse the output with tools that expect a JSON there.

Step to Reproduce
Run Hayabusa like this: hayabusa-2.16.0-lin-gnu json-timeline -d '/image/Windows/System32/winevt/Logs/' -L -o '/tmp/hayabusa-test.jsonl' and look at the output

Expected behavior
Events that don't generate any details should have a Details key with the value { }.

Screenshots

(taken from an older version of Hayabusa, but the problem stands)

Environment:

• OS: Linux
• hayabusa version: 2.16.0

Additional context