fix(oauth): fix OAuth token authentication flow for existing installations

ts/bunq.classes.session.ts

@@ -24,14 +24,16 @@ export class BunqSession {
   /**
    * Initialize a new bunq API session
    */
-  public async init(deviceDescription: string, permittedIps: string[] = []): Promise<void> {
-    // Step 1: Installation
-    await this.createInstallation();
+  public async init(deviceDescription: string, permittedIps: string[] = [], skipInstallationAndDevice: boolean = false): Promise<void> {
+    if (!skipInstallationAndDevice) {
+      // Step 1: Installation
+      await this.createInstallation();
+      
+      // Step 2: Device registration
+      await this.registerDevice(deviceDescription, permittedIps);
+    }
     
-    // Step 2: Device registration
-    await this.registerDevice(deviceDescription, permittedIps);
-    
-    // Step 3: Session creation
+    // Step 3: Session creation (always required)
     await this.createSession();
   }