There are three export options for exporting a PSBT.
The default option previously only put derivation path suffixes for pubkeys
(paths relative to the intermediate xpub), now it puts the full path
(if is known by the keystore).
The "export for hardware device; include xpubs" option works same as before:
it puts both full paths and also global xpubs into the PSBT.
Hence the difference between the default option and the "include xpubs" option
is now only that the latter puts global xpubs into the PSBT.
This change is largely made for user-convenient in mind.
Now exporting a PSBT should be less error-prone: particularly for the
single-signer coldcard with sdcard usage, the default option will now work.
closes#5969
related #5955
c81551299e