Don't include _placementDirty in loaded()

loaded() is an indication of data completeness, not rendering quiescence. Transitory effects (transitions, cross-fading, collision fading) are not included by design.

src/ui/map.js

@@ -1420,7 +1420,7 @@ class Map extends Camera {
      * @returns {boolean} A Boolean indicating whether the map is fully loaded.
      */
     loaded() {
-        if (this._styleDirty || this._sourcesDirty || this._placementDirty)
+        if (this._styleDirty || this._sourcesDirty)
             return false;
         if (!this.style || !this.style.loaded())
             return false;