fix: remove role binding to legacy service account name

[razvan]

Description

Fixes #1005

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added

[nightkr]

LGTM otherwise

[lfrancke]

Should this appear in the release notes?

[razvan]

Release Notes

This release removes support for previously deprecated product service accounts. Deprecated service accounts named {product_name}-serviceaccount are ignored. Instead, product workloads use service accounts named
{resource_name}-serviceaccount where resource_name is the stacklet (or cluster) name as defined in the cluster resource.

[razvan]

Should this appear in the release notes?

added RN