[REQUEST] Only import mesh objects when using "Import FBX" node

**Describe the bug**
Error and sometimes Blender crashes when importing an FBX file, then trying to select faces on it.

**To Reproduce**
Steps to reproduce the behavior:
1. Use an Import FBX node, with valid path, generate UVs
2. Connect to a Select all Node
3. Preview Select all Node
4. Error appears as in screenshot attached

**Expected behavior**
I'd expect that I'm able to select faces on the object as in Edit mode, and continue to manipulate the model

Other Notes:

These were not the first nodes I added, I was mid way through a project, which is attached
[ImportFbxError.zip](https://github.com/aachman98/Sorcar/files/4639018/ImportFbxError.zip)

Model I imported is very simple, it's also included

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Desktop (please complete the following information):**
- OS: Windows 10
- see attached system-info.txt for Blender version, sorcar version and everything else

该问题涉及 Sorcar 中的 'Import FBX' 节点。Sorcar 是一个用于程序化建模的 Blender 插件。检查该节点的实现，可能位于类似 `import_fbx.py` 的文件中，或位于 nodes 模块内。这个 bug 表明导入后选择面时会发生崩溃，说明网格数据处理或选择状态可能存在问题。首先使用提供的 FBX 文件和项目复现错误，然后跟踪导入和选择逻辑，以确定网格对象或其面数据在哪个环节变得无效。

由索引模型根据 Issue 内容生成。