Growatt SFP-5000US/ES Support?

**Describe the problem you have/What new integration you would like**
I've got some of the Growatt SFP-5000US/ES working with the ShineWifi-F that they ship with them right now using the following:

```
output:
# Blue Led
- id: light_bl
platform: gpio
pin: 16
# Green Led
- id: light_gr
platform: gpio
pin: 0
# Red Led
- id: light_rd
platform: gpio
pin: 2

uart:
- id: uart1
baud_rate: 9600
tx_pin: GPIO1
rx_pin: GPIO3

modbus:
uart_id: uart1
flow_control_pin: GPIO4

sensor:
- platform: growatt_solar
update_interval: 10s

inverter_status:
name: "${device_name} Status Code"

phase_c:
voltage:
name: "${device_name} AC Voltage"
current:
name: "${device_name} AC Current"
filters:
- multiply: 0.001
active_power:
name: "${device_name} AC Power"

pv1:
voltage:
name: "${device_name} PV Voltage"
current:
name: "${device_name} PV Current"
filters:
- multiply: 0.1
active_power:
name: "${device_name} PV Active Power"

active_power:
name: "${device_name} Grid Active Power"

pv_active_power:
name: "${device_name} PV Active Power"

frequency:
name: "${device_name} Frequency"

energy_production_day:
name: "${device_name} Today's Generation"
filters:
- multiply: 0.00001

```
However, the Frequency and PV Voltage are 0 as is the PV Active Power.

I saw that there was a commit from 4 days ago that might improve matters but not sure so I wanted to formally ask for support for the SFP series since this is a VERY popular model.

**Please describe your use case for this integration and alternatives you've tried:**
I've tried using both of these: https://github.com/WilbertVerhoeff/Growatt without any luck. The -S works about as well as the above.

**Additional context**
N/A

Start with the supplied YAML configuration and the existing growatt_solar platform, focusing on how the SFP-5000US/ES reports frequency, PV voltage, and PV active power over the shown UART/Modbus setup. Compare the behavior with the recent commit mentioned in the request; done means those reported values work correctly for this inverter series.

Written by the indexing model from the issue text.