Expose AwardEmoji in GraphQL

Problem to solve

We should expose AwardEmojis on the following GraphQL types:

• Types::Notes::NoteType
• Types::MergeRequestType
• Types::IssueType

This should be done using an Interface so the field can be shared, similar to the existing Types::Notes::NoteableType interface. The field in the interface should return [Types::AwardEmojis::AwardEmojiType].