BluetoothGATTCharacteristic.properties should expose a dictionary rather than an array or bitfield about web-bluetooth

[armansito]

The extended properties are present in few cases anyway, so it may not be such a bad requirement to have the UA discover the characteristics and read the value of the Characteristic Extended Properties descriptor before exposing the characteristic. To me it seems more natural to incorporate this into the service/characteristic discovery process.

[jyasskin]

'k, initially, let's have properties return a plain value. We can change it before release if we eventually decide saving the radio round trips is worth the inconvenience.