Don't panic if we fail to parse U2FRegistration data (#17304) (#17371)

Backport #17304

Downgrade logging statement from Fatal to Error so that errors parsing
U2FRegistration data does not panic; instead, the invalid key will be
skipped and we will attempt to parse the next one, if available.

Signed-off-by: David Jimenez <dvejmz@sgfault.com>

Co-authored-by: David Jimenez <dvejmz@users.noreply.github.com>

models/u2f.go

@@ -52,7 +52,7 @@ func (list U2FRegistrationList) ToRegistrations() []u2f.Registration {
 	for _, reg := range list {
 		r, err := reg.Parse()
 		if err != nil {
-			log.Fatal("parsing u2f registration: %v", err)
+			log.Error("parsing u2f registration: %v", err)
 			continue
 		}
 		regs = append(regs, *r)