Show total value label on stacked bar charts

[markov00]

Is your feature request related to a problem? Please describe.
Instead of showing single values for every single bar in a stacked chart, we can provide the option to show the total sum.

Describe the solution you'd like
We can probably introduce a setting in the DisplayValueSpec to specify if we want to see single value or the sum.
See the linked kibana issue for more details

Kibana Cross Issues

• [Lens] Display total value on top of each bar in the vertical bar chart kibana#55262