fix(app): display robot ip not robot ip subnet base (#4411)

pr #4372 (ac74c12) added the netmask
package (https://www.npmjs.com/package/netmask) to parse the robot's networking
response of CIDR-format ip/subnetbits into a separate ip and subnet mask.
Unfortunately, that PR was building a Netmask object and then using its base
member to represent the IP address. However, a Netmask object only represents
information _about the subnet_, not about a specific ip; the base attribute is
the base address of the subnet, e.g. ip & subnetmask.

Instead, split off the CIDR suffix and use the result as the IP address.

app/src/http-api-client/networking.js

@@ -219,7 +219,7 @@ export const makeGetRobotNetworkingStatus = (): GetNetworkingStatusCall =>
             if (iface.ipAddress != null) {
               try {
                 const block = new Netmask(iface.ipAddress)
-                ipAddress = block.base
+                ipAddress = iface.ipAddress.split('/')[0]
                 subnetMask = block.mask
               } catch (e) {
                 // just use what was passed if unable to parse