docs: Add labels to default values

[johnnyhuy]

Added the labels value to the default values.yaml to give end-users visibility on being able to add labels to individual workloads and global.

This prevents us from digging into helper templates to understand how labels are being applied.

[henryrecker-pingidentity]

This has been added in the latest release. See the release notes - https://helm.pingidentity.com/release-notes/currentRelease/