android: Backup shared preferences where applicable

src/android/app/src/main/res/xml/data_extraction_rules.xml

@@ -13,4 +13,8 @@
         domain="external"
         path="." />
 
+    <include
+        domain="sharedpref"
+        path="." />
+
 </full-backup-content>

src/android/app/src/main/res/xml/data_extraction_rules_api_31.xml

@@ -14,6 +14,10 @@
             domain="external"
             path="." />
 
+        <include
+            domain="sharedpref"
+            path="." />
+
     </cloud-backup>
 
     <device-transfer>
@@ -30,6 +34,10 @@
             domain="external"
             path="." />
 
+        <include
+            domain="sharedpref"
+            path="." />
+
     </device-transfer>
 
 </data-extraction-rules>