Fix proto map

[roaminro]

Brief description

Remove inheritance for the ProtoMap class as this generates compilation errors because of signatures mismatch between parent and child classes

Checklist

• [x] I have built this pull request locally
• [x] I have ran the unit tests locally
• [x] I have manually tested this pull request
• [x] I have reviewed my pull request
• [x] I have added any relevant tests