Era should not have a content, only a title

[DegrangeM]

https://h5p.org/node/1143564

[DegrangeM]

I might be wrong, the link https://timeline.knightlab.com/docs/json-format.html#json-text is about the version 3 of the timeline and h5p use the version 2. The text attribute can be find here in the v2 : https://github.com/NUKnightLab/TimelineJS#json
but strangely it is not here https://github.com/NUKnightLab/TimelineJS#jsonp- making me think that they have probably fixed it in the jsonp example but not in the json example.

But I checked very quickly the source code of the v2 and the text value seems used in code. But I didn't check if it is really displayed or not.