[Lens] Percentage charts can have gaps in a series

[dej611]

Kibana version: master as fe1ae92 (> 7.12)

Describe the bug:

Due to Chromium bug: https://bugs.chromium.org/p/chromium/issues/detail?id=1163912

When using area percentage chart with a date histogram, if one of the series has no value for the time bucket, the chart may be rendered with a gap. The gap can be in any part of the chart (also within two series - so not directly as this issue).

Steps to reproduce:

1. Create a new date histogram in Lens with the flight sample data
2. Add Count of Records as Vertical axis
3. Add Top values of FlightDelayTypeasBreak down by`

Expected behavior:

Either 100% fill or 0%. No intermediate area, nor gaps.

Screenshots (if relevant):

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[flash1293]

@dej611 is there something we can/should do from the consumer side?

[dej611]

It seems like filling all the missing buckets with 0 fixes the issue: https://codesandbox.io/s/blue-microservice-b3mf9?file=/src/App.tsx

[flash1293]

Sounds like a good workaround.