Issues with SecureStorage Android backup settings

### Type of issue

Missing information

### Description

The page seems to mention `` as a backup exclusion configuration.
But the settings are stored using the `${applicationId}.microsoft.maui.essentials.preferences.xml` format. This mismatch causes the backup configuration in the documentation to not work properly.

The settings in the documentation also show an `` tag. Including a tag like this in the configuration can have some unintended side effects.
Adding 1 or more include tag to the configuration tells the backup system to backup nothing but the include tags.
Omitting the `include` tag and just adding the `exclude` tag (with the proper path) should be enough for SecureStorage purposes.

The configuration syntax also only applies to Android 11. The configuration syntax for Android 12 and up is missing.
https://developer.android.com/guide/topics/data/autobackup#include-exclude-android-12

### Page URL

https://learn.microsoft.com/en-us/dotnet/maui/platform-integration/storage/secure-storage?view=net-maui-8.0&tabs=android

### Content source URL

https://github.com/dotnet/docs-maui/blob/main/docs/platform-integration/storage/secure-storage.md

### Document Version Independent Id

d8f68de5-3f19-8731-e8ec-c9a40f85b3e3

### Article author

@davidbritch

### Metadata

* ID: d8f68de5-3f19-8731-e8ec-c9a40f85b3e3
* Service: **dotnet-mobile**
* Sub-service: **dotnet-maui**