fix(operator): Skip updating annotations for serviceaccounts

[periklis]

What this PR does / why we need it:
The following PR disables a total overwrite of the serviceaccount annotations and keeps relying on merging them only. This can lead to unwanted reconciliation across operators sharing ownership on specific annotations (e.g. OCP 4.16 adds and owns config.openshift.io/serving-cert-secret-name) .Although none of the manifested serviceaccount resources in our code based makes use of custom annotations, the patch makes the mutate function future proof.

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
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[JoaoBraveCoding]

lgtm