When a remote view update doesn't succeed there's a log message
saying "Error applying view update...".
This message had log level ERROR, but it's not really a hard error.
View updates can fail for a multitude of reasons, even during normal operation.
A failing view update isn't fatal, it will be saved as a view hint a retried later.
Let's change the log level to WARN. It's something that shouldn't happen too much,
but it's not a disaster either.
ERROR log level causes trouble in tests which assume that an ERROR level message
means that the test has failed.
Refs: https://github.com/scylladb/scylladb/issues/15046#issuecomment-1712748784
For local view updates the log level stays at "ERROR", local view updates shouldn't fail.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
Closesscylladb/scylladb#15640