Health check for Table Storage fails when table name is not provided

There is a bug in AzureHealthCheckBuilderExtensions.AddAzureTableStorageCheck where the health check fails if a table name is not provided because it attempts to get a table with a "null" name.

Likewise, if the name is passed in, the health check fails to actually check that the table exists.

Lines 73-78 currently read:

                    if (String.IsNullOrWhiteSpace(tableName))
                    {
                        var table = tableClient.GetTableReference(tableName);

                        result = await table.ExistsAsync();
                    }

Line 73 should be: if (!String.IsNullOrWhiteSpace(tableName))

dotnet-architecture / HealthChecks

Health check for Table Storage fails when table name is not provided #73