NetworkHttp only allow MIJIN_TEST type

[rg911]

Only the MIJIN Test network type is allowed in the NetworkHttp.getNetworkType which seems wrong

[rg911]

@dgarcia360 @evias

[dgarcia360]

The endpoint /network returns the info available in the rest configuration file. Although every node/network could change this value, the former SDK devs decided to parse mijinTest to NetworkType.MIJIN_TEST. However, this configuration file could contain any invalid value, so it might be time to change how we get the network type.

As a potential solution, NetworkHttp.getNetworkType() could parse the version property from the first block header.

Read more on how block header's version property is read.

[rg911]

Discussed with @evias , We decided to use Node/info endpoint's networkIdentifier instead