Ref #1100 , tickmode set to invalid value in mpltools (#1101)
Ref #1100 , tickmode set to invalid value in mpltools (#1101)

* basevalidator throws an error on the boolean
plotly/python-api,plotly/python-api,plotly/python-api,plotly/plotly.py,plotly/plotly.py,plotly/plotly.py