Steps for reproduction:

1) Open the scene `t1` or create lightmap static cube and plane and set directional light to baked
2) Ensure that Precomputed Realtime GI and Baked GI are enabled
3) Disable auto mode and generate the lighting
3) Switch the scene visualization mode to indirect
4) Observe that realtime lightmaps are generated
5) Disable Precomputed Realtime GI and observe that realtime lightmaps are now black
6) Generate the lighting again (while precomputed Realtime GI is still disabled)
7) Observe that no realtime GI lightmap data exists (correctly)

Notes:
- Not a regression, the feature was always working like this
- This is only an issue when auto mode is disabled
- When Precomputed Realtime GI is disabled, the pipeline doesn't go through all the rendering process so not all the data is cleared. Ideally, realtime lightmap data should be cleared completely once Realtime GI is disabled
- Screenshots below show how the current workflow is executed