fix(cmake): correct ARM64 architecture detection on Linux

[Eatgrapes]

I found that in the Linux ARM64 environment, when using the OpenGL sample in the Linux CMake setup, the build failed due to mistakenly using the x86 dependency (libLive2DCubismCore.a). CMake lacked support for ARM64, but actually there was an ARM64 version of the dependency available. Therefore, I added a conditional check to resolve this issue

[wada-at-live2d-com]

@Eatgrapes

Thank you for submitting the pull request!

Indeed, CMake did not support ARM64 builds. (However, one of the reasons for this is that ARM64 is in an experimental position.)
This fix looks very useful, but there are some concerns.
The following set_target_properties points to the x86_64 Core. I think this should also be modified to be switchable with ARM64.
https://github.com/Live2D/CubismNativeSamples/pull/54/files#diff-bb8cf2e6f6b152ae88451012fa7dd710411294a344b0a97b92995df18fbf7bf2R69-R73

I don't think this commit's fix alone will work on ARM64, so please make the correction if possible.

[Eatgrapes]

@Eatgrapes

Thank you for submitting the pull request!

Indeed, CMake did not support ARM64 builds. (However, one of the reasons for this is that ARM64 is in an experimental position.) This fix looks very useful, but there are some concerns. The following set_target_properties points to the x86_64 Core. I think this should also be modified to be switchable with ARM64. https://github.com/Live2D/CubismNativeSamples/pull/54/files#diff-bb8cf2e6f6b152ae88451012fa7dd710411294a344b0a97b92995df18fbf7bf2R69-R73

I don't think this commit's fix alone will work on ARM64, so please make the correction if possible.

Okay,I changed this file again,please review