[realsense2] Update to 2.56.2

[MonicaLiu0311]

Fixes #38635. Update realsense2 to 2.56.2.
Remove outdated patches fix-osx.patch and ${ARM64_DETECTION_FIX}.
Add and fix dependency nlohmann-json.
Add fix-android-prefix-path.patch to fix android prefix path.

Feature openni2 is tested successfully in the following triplets:

x86-windows
x64-windows

Feature tools is tested successfully in the following triplet:

x86-windows
x64-windows
x64-windows-static

The usage test passed on x64-windows (header files found).

• Changes comply with the maintainer guide.
• SHA512s are updated for each updated download.
• The "supports" clause reflects platforms that may be fixed by this new version.
• Any fixed CI baseline entries are removed from that file.
• Any patches that are no longer applied are deleted from the port's directory.
• The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
• Only one version is added to each modified port's versions file.

[MonicaLiu0311]

Error on Android:

[221/222] cd /mnt/vcpkg-ci/b/realsense2/arm-neon-android-dbg && /android-ndk-r27c/toolchains/llvm/prebuilt/linux-x86_64/bin/llvm-ar -M < /mnt/vcpkg-ci/b/realsense2/arm-neon-android-dbg/realsense2-all.ar
FAILED: /librealsense2-all.a 
cd /mnt/vcpkg-ci/b/realsense2/arm-neon-android-dbg && /android-ndk-r27c/toolchains/llvm/prebuilt/linux-x86_64/bin/llvm-ar -M < /mnt/vcpkg-ci/b/realsense2/arm-neon-android-dbg/realsense2-all.ar
/android-ndk-r27c/toolchains/llvm/prebuilt/linux-x86_64/bin/llvm-ar: error: /librealsense2-all.a: Permission denied
ninja: build stopped: subcommand failed.

[dg0yt]

error: /librealsense2-all.a: Permission denied

This seems to be lacking a prefix path and should be fixed as part of the update.