[WinUI] Implicit style overrides are not applied

It appears that implicit styles defined within `XamlControlsResources` are not applied properly, which means that the WinUI toolkit does not actually apply any implicit styles. This is reproducible outside of WinUITests and the samples app (see the zipfile below).

[WinUiStylesTest.zip](https://github.com/user-attachments/files/22893098/WinUiStylesTest.zip)

### Other Solutions Attempted
#### Moving `CalciteResources` outside of `XamlControlsResources`
```

```
This does not work properly as styles that have not been overridden (which is most of them) do not honor theme colors.

Start with the attached WinUiStylesTest.zip reproduction, then compare its resource setup with WinUITests and the samples app. Investigate the XamlControlsResources and CalciteResources merge order and verify that implicit styles apply while non-overridden styles still honor theme colors.

Written by the indexing model from the issue text.