[KPI with trendline] Time comparison isn't displayed when the value is stable and equal to 0

[ValentinC-BR]

When a KPI is equal to 0 during 2 periods, the time comparison (+ 0%) isn't displayed

How to reproduce the bug

1. Create a KPI with trendline
2. Write "0" in Metrics / Custom SQL
3. Chose time comparison period = 1
4. Run

Expected results

"+ 0%" (and the subheader !) should be displayed next to the number

Actual results

There is no subheader nor time comparison.
However, this works with stable trendlines not equal to 0

Screenshots

Environment

(please complete the following information):

• browser type and version: Google Chrome Version 94.0.4606.71 (Oficial build) (x86_64)
• superset version: 1.3.0
• python version: 3.7.9
• node.js version: doesn't apply, I run on Kubernetes, using gunicorn as server
• source : AWS Athena
• any feature flags active: /

Checklist

Make sure to follow these steps before submitting your issue - thank you!

• I have checked the superset logs for python stacktraces and included it here as text if there are any.
• I have reproduced the issue with at least the latest released version of superset.
• I have checked the issue tracker for the same issue and I haven't found one similar.

Additional context

Add any other context about the problem here.

[stale]

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[ValentinC-BR]

I may have been too evasive on this point.
What would be nice would be to display a subheader whether there is a change or not.

Otherwise, we have this kind of graphical incoherences :

[rusackas]

This looks to be resolved by the linked PR, so I'll go ahead and close it. If I'm misinterpreting here, say the word and we can re-open this :)