Remove remaining references to model.NewXX (#28678)

And we remove the deprecated functions to force uses
only of the new function.
```release-note
NONE
```

server/public/model/builtin.go

@@ -3,12 +3,6 @@
 
 package model
 
-// These functions are deprecated. Please use only NewPointer.
-func NewBool(b bool) *bool       { return &b }
-func NewInt(n int) *int          { return &n }
-func NewInt64(n int64) *int64    { return &n }
-func NewString(s string) *string { return &s }
-
 // NewPointer returns a pointer to the object passed.
 func NewPointer[T any](t T) *T { return &t }