Implement projectable GetId for UserGroup

src/Tgstation.Server.Host/Authority/IUserGroupAuthority.cs

@@ -33,6 +33,16 @@ namespace Tgstation.Server.Host.Authority
 		[TgsAuthorize(AdministrationRights.ReadUsers)]
 		RequirementsGated<AuthorityResponse<UserGroup>> GetId(long id, bool includeJoins, CancellationToken cancellationToken);
 
+		/// <summary>
+		/// Gets the <see cref="UserGroup"/> with a given <paramref name="id"/>.
+		/// </summary>
+		/// <typeparam name="TResult">The result type after projection.</typeparam>
+		/// <param name="id">The <see cref="Api.Models.EntityId.Id"/> of the <see cref="UserGroup"/>.</param>
+		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
+		/// <returns>A <see cref="RequirementsGated{TResult}"/> <see cref="Projectable{TQueried, TResult}"/> <see cref="User"/> for <typeparamref name="TResult"/>.</returns>
+		RequirementsGated<Projectable<UserGroup, TResult>> GetId<TResult>(long id, CancellationToken cancellationToken)
+			where TResult : notnull;
+
 		/// <summary>
 		/// Gets all registered <see cref="UserGroup"/>s.
 		/// </summary>

src/Tgstation.Server.Host/Authority/UserGroupAuthority.cs

@@ -111,6 +111,23 @@ namespace Tgstation.Server.Host.Authority
 					return new AuthorityResponse<UserGroup>(userGroup);
 				});
 
+		/// <inheritdoc />
+		public RequirementsGated<Projectable<UserGroup, TResult>> GetId<TResult>(long id, CancellationToken cancellationToken)
+			where TResult : notnull
+			=> new(
+				() => Flag(AdministrationRights.ReadUsers),
+				() => Projectable<UserGroup, TResult>.Create(
+					QueryableImpl(true)
+						.Where(x => x.Id == id),
+					projectable =>
+					{
+						if (projectable == null)
+							return Gone<TResult>();
+
+						return new AuthorityResponse<TResult>(projectable.Result);
+					},
+					cancellationToken));
+
 		/// <inheritdoc />
 		public RequirementsGated<Projectable<UserGroup, TResult>> Read<TResult>(CancellationToken cancellationToken)
 			where TResult : notnull