Fix: Prevent liquid leaking through effector with default settings

When a liquid is created together with collision/effector with default
settings, it often happens that the liquid is leaking through the solid
object/effector.

Change the CFL default value to decrease the chance of this happening.
There appears to be no noticeable performance impact in common cases.

Pull Request: https://projects.blender.org/blender/blender/pulls/120355

source/blender/makesdna/DNA_fluid_defaults.h

@@ -154,7 +154,7 @@
     .time_per_frame = 0.0f, \
     .frame_length = 0.0f, \
     .time_scale = 1.0f, \
-    .cfl_condition = 4.0f, \
+    .cfl_condition = 2.0f, \
     .timesteps_minimum = 1, \
     .timesteps_maximum = 4, \
     .slice_per_voxel = 5.0f, \

source/blender/makesrna/intern/rna_fluid.cc

@@ -2465,7 +2465,10 @@ static void rna_def_fluid_domain_settings(BlenderRNA *brna)
 
   prop = RNA_def_property(srna, "use_adaptive_timesteps", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, nullptr, "flags", FLUID_DOMAIN_USE_ADAPTIVE_TIME);
-  RNA_def_property_ui_text(prop, "Use Adaptive Time Steps", "");
+  RNA_def_property_ui_text(
+      prop,
+      "Use Adaptive Time Steps",
+      "Lets the solver automatically decide when to perform multiple simulation steps per frame");
   RNA_def_property_update(prop, NC_OBJECT | ND_MODIFIER, "rna_Fluid_datacache_reset");
 
   prop = RNA_def_property(srna, "timesteps_min", PROP_INT, PROP_NONE);