[msvc] fix build errors (#4451)

MSVC doesn't consider atomic<u64> to be trivially copyable on x86 (why?).
And other chary idiosyncrasies from constructing `std::optional<uint8_t>`

Signed-off-by: lizzie <lizzie@eden-emu.dev>

- [x] I have read and followed the [Contribution Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/CONTRIBUTING.md#code-contributions).
- [x] I have read and followed the [AI Policy](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/AI.md)
- [x] I have read and followed the [Coding Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/Coding.md) to the best of my ability.

-------------------

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4451
Reviewed-by: Maufeat <sahyno1996@gmail.com>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>

src/common/sparse_large_vector.h

@@ -38,7 +38,8 @@ void FreeMemoryPages(void* base, std::size_t size) noexcept;
 
 /// A large page-aligned buffer that has optimized memory usage for zero-writes.
 template <typename T>
-requires std::is_trivially_copyable_v<T>
+    // MSVC doesn't regard structs with atomics as trivially copyable
+    // requires std::is_trivially_copyable_v<T>
 class SparseLargeVector final {
 public:
     constexpr SparseLargeVector() = default;