test: pass the depth map BlockCache::build now requires

text_font_rendering.rs still called BlockCache::build with the pre-
depth-map signature, so 'cargo test' failed to compile on main. Pass an
empty map — the test exercises glyph tessellation, not draw order.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/text_font_rendering.rs

@@ -49,7 +49,7 @@ fn expand_block_mtext(
 
     let ins = Insert::new("LABEL_BLOCK", insert_at);
     doc.add_entity(EntityType::Insert(ins.clone())).unwrap();
-    let cache = BlockCache::build(&doc, 1.0, [0.0, 0.0, 0.0, 1.0]);
+    let cache = BlockCache::build(&doc, 1.0, [0.0, 0.0, 0.0, 1.0], &Default::default());
     expand_insert(
         &cache,
         &ins,