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.
(these games were made to also be played in co-op, during 1.6 Eric forgot to add the ability to register games in Campaign. Those a mod was required to play such gamemodes in co-op. But thanks to now added Campaign support, there's no more need of such a mod.)
