Try quick way first and fall back to robust way if it fails.

[madchutney]

Description

A fix was added in the last release to handle board detection when the a debug probe was added. This however meant that the detection was an order of magnitude slower.

This change tries the original quick way first and then fall back to the more robust way. This means for the majority of use cases it will be quicker but still work (albeit slower when the debug probe is connected).

Pull request type

[x] Fix
[ ] Refactor
[ ] Target update
[ ] Functionality change
[ ] Docs update
[ ] Test update
[ ] Breaking change

Testing

Before change:

▶ time mbedls   
| platform_name | platform_name_unique | mount_point   | serial_port            | target_id                | daplink_version |
|---------------|----------------------|---------------|------------------------|--------------------------|-----------------|
| K64F          | K64F[0]              | /Volumes/MBED | /dev/tty.usbmodem14202 | 02400201CCF63E703108C3C8 | 0201            |
mbedls  1.30s user 0.17s system 85% cpu 1.717 total

After change:

▶ time mbedls
| platform_name | platform_name_unique | mount_point   | serial_port            | target_id                | daplink_version |
|---------------|----------------------|---------------|------------------------|--------------------------|-----------------|
| K64F          | K64F[0]              | /Volumes/MBED | /dev/tty.usbmodem14202 | 02400201CCF63E703108C3C8 | 0201            |
mbedls  0.38s user 0.12s system 90% cpu 0.552 total
(ls_test)