Remove Zero Downtime upgrade warning for Helm charts
What does this MR do and why?
This change removes a warning note from the documentation about GitLab upgrades. The removed section was alerting users that they cannot perform zero-downtime upgrades when using Helm chart installations, and mentioned that while GitLab Operator provides some support for this, it has known limitations. By removing this note, the documentation now focuses solely on the general zero-downtime upgrade process without calling out these specific deployment method restrictions.
Relates to:
Edited by Nick Westbury