fix(android): use reactApplicationContext.currentActivity in stepUp and openAdminPortal

Author: dianaKhortiuk-frontegg

android/src/main/java/com/frontegg/reactnative/FronteggRNModule.kt

@@ -169,7 +169,7 @@ class FronteggRNModule(val reactContext: ReactApplicationContext) :
 
   @ReactMethod
   fun stepUp(maxAgeSeconds: Double, promise: Promise) {
-    val activity = currentActivity
+    val activity = reactApplicationContext.currentActivity
     if (activity == null) {
       promise.reject("NO_ACTIVITY", "Current activity is null")
       return
@@ -219,7 +219,7 @@ class FronteggRNModule(val reactContext: ReactApplicationContext) :
 
   @ReactMethod
   fun openAdminPortal(promise: Promise) {
-    val activity = currentActivity
+    val activity = reactApplicationContext.currentActivity
     if (activity == null) {
       promise.reject("NO_ACTIVITY", "Cannot open Admin Portal without an active Activity")
       return