Fix 800-series (telnet): manual login + robust single-line command read

[seadillpicklerooster]

What

Makes the WattBox 800-series (WB-800 / WB-820, IP models) actually work over the IP driver. Tested against real WB-800-IPVM-12 and WB-820-IPVM-12, firmware 2.10.0.0, over telnet (port 23). This addresses eseglem/hass-wattbox#55 (and the long-standing "adds but no entities" reports).

The problems (all in driver/async_driver.py)

1. Telnet auth fails. scrapli's in-channel telnet auth sends credentials the device rejects as Invalid Login (the WattBox presents a plain Username: / Password: prompt that scrapli's handshake doesn't satisfy). Result: ScrapliTimeout/ScrapliAuthenticationFailed during setup.
2. Command reads time out. _send_command relies on scrapli's _read_until_prompt(), but this protocol has no real prompt (replies are bare ?Key=value\n lines), so it reads until timeout.
3. No-echo parse bug. _send_command does split_response[1], assuming the device echoes the command on line 0 and the reply on line 1. Over telnet these units do not echo, so it IndexErrors (or mis-parses) — the classic "adds, no entities, no error" symptom.

The fix

• Auth: for telnet transports, set auth_bypass=True and perform the Username:/Password: handshake manually in on_open. SSH is untouched (asyncssh still authenticates; the manual login is gated on transport in ("telnet","asynctelnet")).
• Command read/parse: read the matching reply line directly with re.compile(b"(?m)^" + re.escape(key) + b"=(.*)") (or OK|#Error for ! commands). This is no-echo safe and tolerates spaces/commas in values (e.g. ?OutletName={Switch},...), which the old \S+ prompt regex could not.

Testing

Validated end-to-end against both units: async_create_ip_wattbox() → async_get_initial() → async_update() returns correct model/firmware/outlet-count, per-outlet names, status, and power (e.g. Switch 47.8 W), and total power/voltage.

Caveat: validated on telnet only (I don't have an SSH-configured unit). The SSH path is left on its original code path, but a second set of eyes / an SSH test would be welcome.