[AusTraits dataset enhancement] Add "time to flowering type" context to `fire_time_from_fire_to_flowering`

[yangsophieee]

As a result of the fire traits workshop, we decided that fire_time_from_fire_to_flowering and other related traits should include times from fire to flowering for both resprouting individuals and individuals germinating from seed after fire. This would be distinguished via a context called "time to flowering type". It seems that there are many studies that do not have this context documented. It needs investigating whether they have information on this context, otherwise we will assign "unknown".

I've made a branch called fix_time_to_flowering_type_context to investigate this.