Fix issues with absolute time unit

I think there are the following issues with {rB5fa6cdb77a98}:
- if we introduce a PROP_UNIT_TIME_ABSOLUTE unit, shouldnt it be visible
to RNA as well?
- seems like a double entry sneaked into that commit?

This is in preparation to use this for render time limit in cycles-x.

ref. T90701

Maniphest Tasks: T90701

Differential Revision: https://developer.blender.org/D12315

source/blender/makesrna/intern/rna_rna.c

@@ -123,7 +123,8 @@ const EnumPropertyItem rna_enum_property_unit_items[] = {
     {PROP_UNIT_AREA, "AREA", 0, "Area", ""},
     {PROP_UNIT_VOLUME, "VOLUME", 0, "Volume", ""},
     {PROP_UNIT_ROTATION, "ROTATION", 0, "Rotation", ""},
-    {PROP_UNIT_TIME, "TIME", 0, "Time", ""},
+    {PROP_UNIT_TIME, "TIME", 0, "Time (Scene Relative)", ""},
+    {PROP_UNIT_TIME_ABSOLUTE, "TIME_ABSOLUTE", 0, "Time (Absolute)", ""},
     {PROP_UNIT_VELOCITY, "VELOCITY", 0, "Velocity", ""},
     {PROP_UNIT_ACCELERATION, "ACCELERATION", 0, "Acceleration", ""},
     {PROP_UNIT_MASS, "MASS", 0, "Mass", ""},

source/blender/python/intern/bpy_props.c

@@ -157,7 +157,6 @@ static const EnumPropertyItem property_subtype_number_items[] = {
      0,
      "Time (Absolute)",
      "Time specified in seconds, independent of the scene"},
-    {PROP_TIME_ABSOLUTE, "TIME_ABSOLUTE", 0, "Time Absolute", ""},
     {PROP_DISTANCE, "DISTANCE", 0, "Distance", ""},
     {PROP_DISTANCE_CAMERA, "DISTANCE_CAMERA", 0, "Camera Distance", ""},
     {PROP_POWER, "POWER", 0, "Power", ""},