[PB-6602] align return values with the server

[TamaraFinogina]

Description

Align return value with what the server expects, remove email encryption for the single recipient function as unused

Checklist

• Changes have been tested locally.
• Unit tests have been written or updated as necessary.
• The code adheres to the repository's coding standards.
• Relevant documentation has been added or updated.
• No new warnings or errors have been introduced.
• SonarCloud issues have been reviewed and addressed.
• QA Passed

Testing Process

unit tests

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud