Goodbye, GraphQL (#24827)

```release-note
NONE
```

server/public/model/team_member.go

@@ -142,9 +142,3 @@ func (o *TeamMember) PreUpdate() {
 func (o *TeamMember) GetRoles() []string {
 	return strings.Fields(o.Roles)
 }
-
-// DeleteAt_ returns the deleteAt value in float64. This is necessary to work
-// with GraphQL since it doesn't support 64 bit integers.
-func (o *TeamMember) DeleteAt_() float64 {
-	return float64(o.DeleteAt)
-}