Increase log level when there is an invalid size value

[aledbf]

What this PR does / why we need it:

Increases the log level to avoid logs like

E1120 17:59:35.050763       7 template.go:764] empty byte size, hence it will not be set.
E1120 17:59:35.051484       7 template.go:764] empty byte size, hence it will not be set.
E1120 17:59:35.051905       7 template.go:764] empty byte size, hence it will not be set.

in the default log level.
This will be partially fixed after #3437

[ElvinEfendi]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf, ElvinEfendi

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