addCartridge operation checks for already deployed cartridges in two places

[Sajith Kariyawasam]

Hi Devs,

I noted that in addCartridge operation, existing cartridge check is done
twice.

In StratosApiV41 --> CartridgeBean cartridgeBean =
StratosApiV41Utils.getCartridgeForValidate(cartridgeType);

Also in CloudcontrollerServiceImpl -->
 cloudControllerContext.getCartridge(cartridgeType)

I think the check in StratosApi (rest endpoint) is redundant, and that is
not a responsibility of rest endpoint, also this will be an overhead to do
a service call.

Any reason for adding it there..?

Thanks,
Sajith