fix(helm chart): provide service account with access to multi-region

[iainsproat]

Description & motivation

When deployed to Kubernetes via Helm Chart, the multi-region config was unable to be mounted to the deployment. This was because the secret was not accessible by the service account.

This PR provides access to the multi-region secret by the service account.

Changes:

To-do before merge:

Screenshots:

Validation of changes:

Checklist:

• My pull request follows the guidelines in the Contributing guide?
• My pull request does not duplicate any other open Pull Requests for the same update/change?
• My commits are related to the pull request and do not amend unrelated code or documentation.
• My code follows a similar style to existing code.
• I have added appropriate tests.
• I have updated or added relevant documentation.

References