test: Update shape drag test
test: Update shape drag test

* Initiate drag move at the shape centre to avoid resizing the shape.

aburato/plotly.js,asolagmbh/plotly.js,plotly/plotly.js,etpinard/plotly.js,asolagmbh/plotly.js,plotly/plotly.js,asolagmbh/plotly.js,plotly/plotly.js,etpinard/plotly.js,iongroup/plotly.js,iongroup/plotly.js,plotly/plotly.js,aburato/plotly.js,etpinard/plotly.js,iongroup/plotly.js