Revert "Bump aosp contacts to target SDK 31"

This reverts commit 36bb30611ffd07e386ef7c2cb2842d90170b6db0.

Reason for revert: IMMUTABLE was added in SDK 23

Change-Id: I2c9487867f76cd46774d4a71900001b0895e0f78
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index b4b15b0..32d6644 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -21,7 +21,7 @@
 
     <uses-sdk
         android:minSdkVersion="21"
-        android:targetSdkVersion="31"/>
+        android:targetSdkVersion="30"/>
 
     <original-package android:name="com.android.contacts"/>