Fixing scope in label templating

[0xffox]

What this PR does / why we need it

Single timescale chart do not renders properly

Which issue this PR fixes

Wrong scope passed into helper function inside range in bgbackrest.yaml

(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)

• fixes #

Special notes for your reviewer

Checklist

• [ ] Chart Version bumped
• [ ] CLA signed

[CLAassistant]

All committers have signed the CLA.