When disconnected from the network interface, VPN should gracefully go to Disconnected state, rather than Try again error dialogs

[stephendonner]

Description

When disconnected from the network interface, VPN should gracefully go to Disconnected state, rather than Try again error dialogs

This is essentially just #22883 continued (fix made things better, but it still happens).

Steps to Reproduce

1. install 1.43.3
2. launch Brave
3. purchase and set up BraveVPN
4. connect to BraveVPN
5. disconnect Wi-Fi (or Ethernet)
6. click on the (currently showing as Connected) VPN button
7. wait

Actual result:

Can't connect to server / Try again

Expected result:

The VPN dialog should just toggle to Disconnected

Reproduces how often:

100%, eventually

Brave version (brave://version info)

Version/Channel Information:

• Can you reproduce this issue with the current release? No
• Can you reproduce this issue with the beta channel? Yes
• Can you reproduce this issue with the nightly channel? No

cc @simonhong @spylogsster @mattmcalister @rebron @bsclifton @MadhaviSeelam @GeetaSarvadnya @srirambv

[stephendonner]

Talked this over with @spylogsster - this is fine as-is, and makes sense to users. Marking as INVALID.