fix(biometric) prompt for fallback credentials when enabled and biometry unavailable on iOS (fix tauri-apps#2632) (tauri-apps#2633)

Author: pjf-dev

.changes/fix-ios-biometry-fallback-auth.md

@@ -0,0 +1,6 @@
+---
+"biometric": patch:bug
+"biometric-js": patch:bug
+---
+
+Fix biometric plugin ignoring fallback logic when biometry status is unavailable or not enrolled on iOS.

plugins/biometric/ios/Sources/BiometricPlugin.swift

@@ -98,23 +98,24 @@ class BiometricPlugin: Plugin {
   }
 
   @objc func authenticate(_ invoke: Invoke) throws {
-    guard self.status.available else {
+    let args = try invoke.parseArgs(AuthOptions.self)
+
+    let allowDeviceCredential = args.allowDeviceCredential ?? false
+
+    guard self.status.available || allowDeviceCredential else {
+      // Biometry unavailable, fallback disabled
       invoke.reject(
         self.status.errorReason ?? "",
         code: self.status.errorCode ?? ""
       )
       return
     }
 
-    let args = try invoke.parseArgs(AuthOptions.self)
-
     let context = LAContext()
     context.localizedFallbackTitle = args.fallbackTitle
     context.localizedCancelTitle = args.cancelTitle
     context.touchIDAuthenticationAllowableReuseDuration = 0
 
-    let allowDeviceCredential = args.allowDeviceCredential ?? false
-
     // force system default fallback title if an empty string is provided (the OS hides the fallback button in this case)
     if allowDeviceCredential,
       let fallbackTitle = context.localizedFallbackTitle,