fix(unity): make single board test procedure more robust

[hfudev]

No description provided.

[horw]

This is very useful!
By the way, I think we don't need the self._ignore_first_ready_pattern attribute, do we?
We can simply press enter every time before expecting. As I see it, it will work the same way.

def _hard_reset(self) -> None:
    if self._hard_reset_func:
        try:
            self._hard_reset_func()
        except NotImplementedError:
            pass
def _get_ready(self, timeout: float = 30) -> None:
   self.confirm_write('\n', expect_pattern=READY_PATTERN_LIST, timeout=timeout)

[hfudev]

yes you're right. the downside of this approach is that, the test menu will be printed again after a reset.

I'd like to keep the code more complicated... and as an exchange, a cleaner output for users.

[hfudev]

Since the error that this PR is fixing is not 100% reproducible, I'll merge it first :D