Reported in ballistica's official discord server:
https://discord.com/channels/1001896771347304639/1218201750440247296/1227731932838760521.
We were calling `_bascenev1.protocol_version()` before SceneAppMode was
activated (by ballistica), which isn't allowed in newer ballistica
versions.
It was the cause of the following traceback:
```sh
$ CMAKE_BUILD_TYPE="Debug" make prefab-gui-debug
BA_WSL_TARGETS_WINDOWS=1 tools/pcommand make_prefab gui-debug
make[1]: Entering directory '/home/rikkolovescats/ballistica'
Lazybuild: skipping "meta" (checked 89 inputs in 0.0026s).
Lazybuild: skipping "assets-cmake" (checked 376 inputs in 0.0018s).
Staging for cmake at build/prefab/full/linux_x86_64_gui/debug...
make[1]: Leaving directory '/home/rikkolovescats/ballistica'
cd build/prefab/full/linux_x86_64_gui/debug && ./ballisticakit
root: BallisticaKit 1.7.34 build 21800.
root: Error loading plugin class 'plugin_manager.EntryPoint'.
Traceback (most recent call last):
File "/home/rikkolovescats/ballistica/build/prefab/full/linux_x86_64_gui/debug/ba_data/python/babase/_plugin.py", line 283, in attempt_load_if_enabled
cls = getclass(self.class_path, Plugin)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/rikkolovescats/ballistica/build/prefab/full/linux_x86_64_gui/debug/ba_data/python/babase/_general.py", line 83, in getclass
module = importlib.import_module(modulename)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.11/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 940, in exec_module
File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
File "/home/rikkolovescats/.ballisticakit/mods/plugin_manager.py", line 70, in <module>
protocol_version = _bs.protocol_version()
^^^^^^^^^^^^^^^^^^^^^^
RuntimeError: Attempting to access SceneAppMode while it is inactive.
```
This commit improves the compatibility layer such that any calls that
require SceneAppMode to be active aren't made before it gets active.
