Error/Fix: “Decryption failed” when importing a p12 certificate into Kleopatra

Error: An error occurred while trying to import the certificate /path/to/cert.p12:
Decryption failed

Fix: import it from the command line with these two commands:
openssl pkcs12 -in cert.p12 | gpgsm --import
gpgsm --call-protect-tool --p12-import --store -P password cert.p12