Fix T74362: Material Preview Assert

When using Material Previews not all uniform blocks were filled. This
patch will add the renderpass_block when drawing the background.

Note that I wasn't able to reproduce the issue on my system, but
according the the backtrace it most likely solves the issue. I let the
reporter test.

source/blender/draw/engines/eevee/eevee_lookdev.c

@@ -176,6 +176,8 @@ void EEVEE_lookdev_cache_init(EEVEE_Data *vedata,
         DRW_shgroup_uniform_block(grp, "grid_block", sldata->grid_ubo);
         DRW_shgroup_uniform_block(grp, "planar_block", sldata->planar_ubo);
         DRW_shgroup_uniform_block(grp, "common_block", sldata->common_ubo);
+        DRW_shgroup_uniform_block(
+            grp, "renderpass_block", EEVEE_material_default_render_pass_ubo_get(sldata));
       }
 
       DRW_shgroup_call(grp, DRW_cache_fullscreen_quad_get(), NULL);