Expose number of DNS query results in connection-related error messages

[atc0005]

Instead of a repeat of #190, the check_imap_mailbox plugin reported the following today:

Additional Info:

CRITICAL: Error connecting to outlook.office365.com

ERRORS

• failed to gather IP Addresses for connection attempts

This is good, since the plugin didn't crash, but it also doesn't note how many query results we started with. Were there literally no results, or were they all IPv6 only?

The error message should be expanded to note the original query results before any potential parsing to drop IPv6-specific entries (or to drop IPv4 entries if the user opted for IPv6-only connectivity).

[atc0005]

Block relevant to the specific error message noted earlier:

check-mail/internal/mbxs/connect.go

Lines 203 to 218 in 2f2d300

	// No IPs remain after filtering against IPv4-only or IPv6-only
	// requirement.
	switch {
	case len(addrs) < 1:
	errMsg := "failed to gather IP Addresses for connection attempts"
	logger.Error().Msg(errMsg)
	return nil, fmt.Errorf(errMsg)
	default:
	logger.Debug().
	Int("count", len(addrs)).
	Str("ips", strings.Join(addrs, ", ")).
	Msg("successfully gathered IP Addresses for connection attempts")
	}

[atc0005]

In addition to that block, other related error messages for mbxs.Connect() should also identify the query results count.