Fix lint error - include database domain before excluding

Added database domain to included paths before excluding pwa_cache.db
to fix FullBackupContent lint error.

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Co-Authored-By: Claude <noreply@anthropic.com>

app/src/main/res/xml/backup_rules.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <full-backup-content>
     <include domain="sharedpref" path="."/>
+    <include domain="database" path="."/>
     <exclude domain="database" path="pwa_cache.db"/>
 </full-backup-content>