fix: restart from WebUI no longer needs the browser tab to stay open

A restart requested from the WebUI (Restart button, firmware upload,
firmware update from URL, settings or customization upload) is set to
PENDING_RESTART and was only escalated to RESTART_REQUESTED when the
WebUI's SystemMonitor polled /rest/systemStatus. If the tab was closed,
nothing ever escalated it and the generic 5 minute status timeout reset
it back to NORMAL, so the restart was dropped and an uploaded firmware
was never booted.

- System::loop() now escalates a pending restart itself if it hasn't been
  picked up within 10 seconds (the SystemMonitor polls every second)
- the generic status reset timeout skips PENDING_RESTART, and its timer is
  cleared whenever the status is back to normal, so a start time left over
  from an earlier status can't reset a later one (e.g. a pending restart
  right after a firmware download) immediately

CHANGELOG_LATEST.md

@@ -32,6 +32,7 @@ This release is based on the latest Espressif/Arduino core version 3. It brings
 
 ## Fixed
 
+- restart from the WebUI (Restart button, firmware/settings upload) only happened while the browser tab stayed open. If the tab was closed the restart was silently dropped after 5 minutes, leaving a new firmware uninstalled. EMS-ESP now restarts on its own if the WebUI hasn't picked up the pending restart within 10 seconds
 - shunting yard show json
 - `system/sendmail` called from a Command or the Scheduler computed its value twice, which stripped the quotes from literal text and then failed on characters like `!`. Also shunting yard treated a `?` inside a quoted string as a ternary, so text like `"too hot?"` returned nothing
 - memory leak when using different timezones for ems-esp and thermostat[#3184](https://github.com/emsesp/EMS-ESP32/issues/3184)