WIP: [Addon] FluxCD: add serviceAccountName support for helm component

[jeffguorg]

Description of your changes

Fixes #645 add support of serviceAccountName for helm component

How has this code been tested?

Checklist

I have:

• [ ] Title of the PR starts with type (e.g. [Addon] , [example] or [Doc]).
• [ ] Updated/Added any relevant documentation and examples.
• [ ] New addon should be put in experimental.
• [ ] Update addon should modify the version in metadata.yaml to generate a new version.