[lldb/crashlog] Update incorrect help message for `--no-crashed-only` option (#91162)

This patch rephrases the crashlog `--no-crashed-only` option help
message. This option is mainly used in batch mode to symbolicate and
dump all the threads backtraces, instead of only doing it for the
crashed thread which is the default behavior.

rdar://127391524



Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>