Fix reality data not being reprojected correctly when its CRS is different than iModel (backport #9059) [release/5.7.x]

[mergify]

There is a bug where when using the reproject parameter of TileTreeReference.createGeometryTreeReference, if the reality data is not in the same CRS than the iModel, the reprojection will put the geometry at the wrong place.

This was because in RealityTileLoader.loadGeometryFromStream, the geometry returned by RealityTileLoader.readGltfAndCreateGeometry is in iModel coordinates, but the reprojection transform is in the reality tree's coordinates.

The fix is to take this difference into account by doing the following:

1. multiply polyface by inverse of tree's iModelTransform to "convert" polyface from iModel CRS->tile tree CRS
2. apply the original reprojection transform xForm
3. multiply by original iModelTransform to convert back from tile tree CRS->iModel CRS

Tested with a couple different iModels with reality data in different CRS. I also added some unit tests for this.

---

This is an automatic backport of pull request #9059 done by Mergify.

[mergify]

Cherry-pick of d122ee6 has failed:

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Changes to be committed:
	new file:   common/changes/@itwin/core-frontend/eringram-rd-reproject-crs_2026-03-04-23-15.json
	modified:   core/frontend/src/internal/tile/RealityTileLoader.ts
	modified:   core/frontend/src/test/tile/RealityTile.test.ts

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   docs/changehistory/NextVersion.md

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[hl662]

@copilot resolve merge conflict using the conflict resolver skill

[Copilot]

@hl662 I've opened a new pull request, #9078, to work on those changes. Once the pull request is ready, I'll request review from you.