Merge "[SettingsProvider] fix NPE introduced by ag/26086453" into main

        final Iterator<Map.Entry<String, Setting>> iterator = mSettings.entrySet().iterator();

        int index = prefix.lastIndexOf('/');

        String namespace = index < 0 ? "" : prefix.substring(0, index);

        Map<String, String> trunkFlagMap =

                mNamespaceDefaults.get(namespace);

        Map<String, String> trunkFlagMap = (mNamespaceDefaults == null)

                ? null : mNamespaceDefaults.get(namespace);

        // Delete old keys with the prefix that are not part of the new set.

        // trunk flags will not be configured with restricted propagation

        // trunk flags will be explicitly set, so not removing them here