add option to return custom fields

[cceyda]

with this PR you can pass return_fields=True and get custom_data/hover_data return too.

Use Case:
pointIndex wasn't equal to the index of the dataframe in my case, that's why I needed to return some additional data about the selected point. can be useful for other cases too, like when you want to access more custom_data fields.

fig = px.scatter(df, x="x", y="y", color="type", hover_data=["index","index2"])

selected_points = plotly_events(fig,click_event=True,select_event=False,return_fields=True)
st.write(selected_points )
# customdata is an array because it didn't return a dict on the javascript side
0:{
"x":4.478600978851318
"y":-2.733484983444214
"pointNumber":181
"pointIndex":181
"curveNumber":0
"customdata":[
0:"5"
1:"10"
]
}

[sebimarkgraf]

@null-jones This feature would be quite useful for a lot of users that need the index in any grouped plots.
Would you consider merging this?

[cceyda]

@sebimarkgraf Until this is merged you can pip install git+https://github.com/cceyda/streamlit-plotly-events/@release to get version including this PR.

[fuubarbaz]

It's been quite for some time. Could you please merge it ?