[native] Fix server list in Dev tools menu

Summary:
On physical devices, the Profile -> Developer tools -> Server list was displaying the localhost as one of default options.

In url-utils.js, the server list was out of sync with rest of the code. It duplicated part of getDevServerHostname() logic, but it used the platform-specific localhost only.

Replaced the duplicated logic with getDevServerHostname() call.

Depends on D6268

Test Plan:
Opened the developer options on both simulator and physical device. Ensured that second option from the list is as follows:

• On simulator it sticks to localhost / 10.0.2.2(Android)
• On physical device it uses the autodetected IP address

Reviewers: ashoat, atul

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D6269