"oops, no device was paired" message on pairing with new flow in /beta

[jaustin]

I went through a pairing flow as follows:

• Start with a V1 that had very old firmware (0234) so didn't show up in the dialog
• fail to find it twice
• swap to a V2 micro:bit with new firmware
• pair successfully

I got a little "oops, no device was paired" message. But pairing was fine. (though the first flash didn't work, about to file that as a new issue)

I wasn't quick enough to catch it as a screenshot, but it was a blue popup message.

[jwunderl]

Same as https://github.com/microsoft/pxt-microbit/issues/5099, fix is in https://github.com/microsoft/pxt/pull/9493