Gameanalytics has errors when generating glue for .net build

[wadlo]

Repro steps:

• follow the guide for compiling on .net on windows
• When you get to the step to generate glue, there are errors.

Godot Engine v4.2.dev.mono.custom_build.92a1333b6 - https://godotengine.org
ERROR: Condition "instance != 0" is true.
   at: GameAnalytics::GameAnalytics (modules\gameanalytics\GameAnalytics.cpp:33)
ERROR: Can't register singleton that already exists: GameAnalytics
   at: (core\config\engine.cpp:263)
OpenGL API 3.3.0 NVIDIA 536.40 - Compatibility - Using Device: NVIDIA - NVIDIA GeForce GTX 1660 SUPER

ERROR: Condition "instance != 0" is true.
   at: GameAnalytics::GameAnalytics (modules\gameanalytics\GameAnalytics.cpp:33)
ERROR: Can't register singleton that already exists: GameAnalytics
   at: (core\config\engine.cpp:263)
ERROR: Condition "instance != 0" is true.
   at: GameAnalytics::GameAnalytics (modules\gameanalytics\GameAnalytics.cpp:33)
ERROR: Can't register singleton that already exists: GameAnalytics
   at: (core\config\engine.cpp:263)

[sabvdf]

I fixed this error in #29, let's see if anyone at GA will merge it since they may want to move to a GDExtension instead.