[AnimationsAPI] Fix modifying layers with behaviours - #689

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v3, actions/setup-dotnet@v4, actions/upload-artifact@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Converting null literal or possible null value to non-nullable type.

Cannot convert null literal to non-nullable reference type.

'RoR2_Base_Common_GlobalTextures.texRampElites_psd' is obsolete: 'Use GameAssetPathsBetter instead.'

'RoR2_Base_Common_GlobalTextures' is obsolete: 'Use GameAssetPathsBetter instead.'

'AddressReferencedAsset.OnAddressReferencedAssetsLoaded' is obsolete: 'This event no longer runs after anything in particular, it gets invoked on RoR2Application.onLoad for backwards compatibility.'

'AddressReferencedAsset.OnAddressReferencedAssetsLoaded' is obsolete: 'This event no longer runs after anything in particular, it gets invoked on RoR2Application.onLoad for backwards compatibility.'

XML comment has syntactically incorrect cref attribute 'HasModdedBodyFlag(CharacterBody, ModdedBodyFlag))'

'AddressReferencedAsset.LoadAssetAsync()' is obsolete: 'If you need to implement this, implement a method that just returns Task.CompeltedTask, loading is now done via LoadAssetAsyncCoroutine instead.'

XML comment has syntactically incorrect cref attribute 'HasModdedBuffFlag(BuffDef, ModdedBuffFlag))'