* [docker_container] Failing on non-string env values (#49843)
* [docker_container] Failing on non-string env values
Fixes#49802
* Clarify failure message
Co-Authored-By: DBendit <David@ibendit.com>
* Fixup from review
(cherry picked from commit d62d7176b0)
* Turn fail into warning for 2.7 backport.
* Fix test for backport
The behaviour in the backport is to warn rather than error
