Known unresolved issues after removing VtEngine / adding VT passthrough

- [x] Reflowing a long line until it wraps results in the cooked read prompt to be misaligned vertically.
- [x] Move the `OSC 0 ; P t BEL` sequence to `WriteWindowTitle` and swap the `BEL` with the `ST` (`ESC \`).
- [x] PowerShell on Windows 10 ships with PSReadLine 2.0.0-beta2 which emits SGR 37/40 instead of 39/49. This results in black spaces when typing and there's no good way to fix that.
- [ ] Translation of `COMMON_LVB_GRID_HORIZONTAL` to `SGR 53` was dropped and may be reintroduced alongside `UNDERSCORE` = `SGR 4`.
- [x] `ScrollConsoleScreenBuffer` destroys grapheme clusters and extended (VT) attributes and could be translated to `DECCRA` and `DECFRA` in the near term. This is important because otherwise `vim` output may loose its extended attributes during scrolling.
- [x] In cmd: `echo ^[[=c` (should return a DA3 report like `^[P!|00000000^[\`, but we now just get `P!|\`).
- [ ] #17817
- [ ] `VtIo::Writer::WriteInfos` should properly verify the width of each individual character.
- [ ] Using `SetConsoleActiveScreenBuffer` destroys grapheme clusters and extended (VT) attributes. It could be translated to VT pages in the long term.
- [ ] A test is missing that ensures that `FillConsoleOutputCharacterW` results in a `CSI n J` during the PowerShell shim.
- [ ] A test is missing that ensures that `PtySignal::ClearBuffer` does not result in any VT being generated.
- [ ] Port the tests over from https://github.com/microsoft/terminal/issues/17801
- [ ] https://github.com/microsoft/terminal/issues/17737
- [x] https://github.com/microsoft/terminal/issues/17709
- [x] https://github.com/microsoft/terminal/issues/17801
- [ ] https://github.com/microsoft/terminal/issues/17874