## Summary
- Wires up the native `fabricCreateViewTransitionInstance` call in
`createViewTransitionInstance` which will create a ShadowNode for old
pseudo element
- Extracts tag allocation logic into a shared `allocateTag()` function
exported from `ReactFiberConfigFabric`
- Imports `allocateTag` in `ReactFiberConfigFabricWithViewTransition`
- Reuses `allocateTag()` in `createInstance` and `createTextInstance`
instead of inline tag incrementing
- Wires up native `fabricSuspendOnActiveViewTransition` call in
`suspendOnActiveViewTransition` which suspends another view transition
when the previous one is not yet finished
## Test plan
- Existing Fabric renderer tests should continue to pass
- ViewTransition instance creation now properly allocates a tag and
calls the native module
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