Perf opportunity, call RoGetActivationFactory much less often in xaml

Nobody has claimed this yet.

### Describe the bug

I traced every RoGetActivationFactory being made when Xaml starts up and I see a lot of calls that can be avoided if the factories were cached like they are in cppwinrt.

```cpp
// When launching the window and letting it paint, I observed
// 206 calls to RoGetActivationFactory or RoGetClassObject
// 68 unique names were passed.
// If cached 138 (206-68) will be saved.
// (206-68)/206 = ~67% calls will be cached.
```

I've got a drop-in replacement for the direct API use that implements caching and can share that with those interested in seeing what effect this has.

### Steps to reproduce the bug

I used the VS debugger ability to trace on method calls, setting breakpoints on these APIs. and launching the bare bones WinUI App sample template.

observe redundant calls

### Expected behavior

no redundancy, DRY.

### Screenshots

_No response_

### NuGet package version

None

### Packaging type

_No response_

### Windows version

_No response_

### IDE

_No response_

### Additional context

_No response_

Start by tracing RoGetActivationFactory and RoGetClassObject in the XAML startup path, using the VS debugger and the bare-bones WinUI App sample described in the issue. Compare the observed calls with the 68 unique names and determine whether caching is safe; done means redundant factory or class-object calls are avoided without changing startup behavior.

Written by the indexing model from the issue text.