fix: allow the object owner to grant and revoke privileges

[yezizp2012]

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What's changed and what's your intention?

Before this, the object owner could not grant or revoke privileges of objects to other users. This PR fixes this issue.

Checklist

• I have written necessary rustdoc comments
• I have added necessary unit tests and integration tests
• I have added test labels as necessary. See details.
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Release note

If this PR includes changes that directly affect users or other significant modifications relevant to the community, kindly draft a release note to provide a concise summary of these changes. Please prioritize highlighting the impact these changes will have on users.

[Rossil2012]

LGTM.