[influxdb] Improve connection handling (#15879)

[influxdb] Improve connection handling (#15879)

* [influxdb] Improve connection handling

Especially for InfluxDB2 the connection check was not properly implemented. It only checked if a connections was ever successfully established. Since we removed the full crash when a write error occured, this lead to a situation where a broken connection was not detected. A ping is now implemented and also a failed write results in a disconnect.

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Signed-off-by: Jan N. Klug <github@klug.nrw>