Multiple static routes inside one private gateway.

### problem

As an admin I want to have possibility to add more than one static route to private gateway.
Unfortunately, I'm not sure if this a bug or a feature.

But if I try to add the second static route (Destination Network CIDR) to Private Gateway, just nothing happens after I push the "Add route" button. Screenshot with example is attached.


### versions

The versions of ACS, hypervisors, storage, network etc..
Current ACS version is 4.20.0.0
Previous vith the same issue: 4.19.1
Hypervisors: XCP-NG 8.2.1

### The steps to reproduce the bug

1. Create new Private Pateway
2. Add first Destination Network CIDR
3. Add second Destination Network CIDR

### What to do about it?

_No response_

Reproduza o problema no CloudStack 4.20.0.0 criando um gateway privado, adicionando um Destination Network CIDR e enviando um segundo por meio do controle “Add route”. Rastreie o ponto de entrada de adição de rotas do gateway privado e verifique se várias rotas são aceitas e se o segundo CIDR é persistido ou relatado com um erro visível.

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