code generated for map[string]interface{} could be simplified

[orian]

https://github.com/PostHog/posthog/pull/31752/files/477c24428b8892ff6b053b75273dbe33be0524b9#r2068284723

Actual:

var v1 interface{}
if m, ok := v1.(easyjson.Unmarshaler); ok {
	m.UnmarshalEasyJSON(in)
} else if m, ok := v1.(json.Unmarshaler); ok {
	_ = m.UnmarshalJSON(in.Raw())
} else {
	v1 = in.Interface()
}

Could be:

v1 := in.Interface()
if m, ok := v1.(easyjson.Unmarshaler); ok {
	m.UnmarshalEasyJSON(in)
} else if m, ok := v1.(json.Unmarshaler); ok {
	_ = m.UnmarshalJSON(in.Raw())
}
(out.Properties)[key] = v1
in.WantComma()