Update main.ino - Remove restartesp from discovery_prefix stanza

[puterboy]

Description:

Revert from original patch as not necessary and also prevents saving of new MQTT variable values
See #1996 (comment)

Checklist:

• The pull request is done against the latest development branch
• Only one feature/fix was added per PR and the code change compiles without warnings
• I accept the DCO.

[1technophile]

Should it be added to the documentation that the gateway needs to be restarted after to republish to the new topic ?

[puterboy]

No - as I detailed at length (maybe too much :)) in several new comments in #1996, a restart is triggered anyway since discovery_prefix is on the same WebUI page as the various MQTT login variables that in turn show (always) show as changed and trigger a configuration backup when setupMQTT() is called which in turn triggers a restart from within setupMQTT() (assuming changes were successful)

Indeed one way or other, most variables end up triggering a restart that way (whether intended or not).. Indeed, as I detail in my comments a restart really shouldn't be necessary for most if not all variables.

Also, saveConfig() is often called twice.

In all the code could deserve some straightening out as its effects are non-obvious and may not be as intended but I understand this may not be a priority.

[1technophile]

We would need some testing to see if the restart from setupMQTT could be avoided, we will keep it for now as I have other PR in stock.
Thanks