Complete eRegenerateKey immediately

[artfwo]

Description

Follow-up to #10855

There's an extra delay unrelated to the network request when regenerating keys, as noted by Valentina. It seems to happen because we wait for TaskControllerAction to time out before transitioning to the next task.

The fix is to complete eRegenerateKey task action immediately, since the actual key regeneration is handled by subsequently launched TaskAddDevice, so there's no need to wait for an async operation.

Reference

VPN-2693

Checklist

• My code follows the style guidelines for this project
• I have not added any packages that contain high risk or unknown licenses (GPL, LGPL, MPL, etc. consult with DevOps if in question)
• I have performed a self review of my own code
• I have commented my code PARTICULARLY in hard to understand areas
• I have added thorough tests where needed

[artfwo]

One testConnection case is failing because the mock response is returned too quickly, this is now fixed in 3a38e6b

[oskirby]

LGTM