fix: remove use of deprecated currentActivity getter (#900)

* fix: remove use of deprecated currentActivity getter

* Fix deprecated currentActivity getter usage

Removed the use of the deprecated currentActivity getter in the picker package.

Author: vonovak

.changeset/healthy-pots-rescue.md

@@ -0,0 +1,5 @@
+---
+"@react-native-documents/picker": patch
+---
+
+fix: remove use of deprecated currentActivity getter

packages/document-picker/android/src/main/java/com/reactnativedocumentpicker/RNDocumentPickerModule.kt

@@ -103,11 +103,7 @@ class RNDocumentPickerModule(reactContext: ReactApplicationContext) :
   }
 
   override fun saveDocument(options: ReadableMap, promise: Promise) {
-    val currentActivity = currentActivity
-    if (currentActivity == null) {
-      rejectWithNullActivity(promise)
-      return
-    }
+    val currentActivity = reactApplicationContext.currentActivity ?: return rejectWithNullActivity(promise)
     if (!promiseWrapper.trySetPromiseRejectingIncoming(promise, "saveDocuments")) {
       return
     }