Binance OnGetTickersAsync throws InvalidDataException

[BZ-CO]

Currently we identify base/quote currencies by calling OnGetMarketSymbolsMetadataAsync().
If instrument is going to be delisted soon it may be removed from the metadata response, while it still remains in the ticker response.
This leads to throwing an exception and failing to return the remaining valid ticker data.

ParseTickerAsync() should be wrapped in try block.

Will submit PR with the fix in a minute.

[jjxtra]

Thank you

[vslee]

Thanks for your contribution! Your code changes are now available in the prerelease build: https://dev.azure.com/DigitalRuby/DigitalRuby/_artifacts/feed/DigitalRuby