Fix background texture render abnormal

[cptbtptpbcptdtptp]

When setting textureFillMode to fill first and then setting texutre, the background texture will render abnormally because the position of the mesh is not updated.

import {
  AssetType,
  BackgroundMode,
  BackgroundTextureFillMode,
  Camera,
  Texture2D,
  WebGLEngine,
} from "@galacean/engine";

WebGLEngine.create({ canvas: "canvas" }).then((engine) => {
  const scene = engine.sceneManager.activeScene;
  const { background } = scene;
  const root = scene.createRootEntity();
  const cameraEntity = root.createChild();
  cameraEntity.addComponent(Camera);
  engine.canvas.width = 480;
  engine.canvas.height = 360;

  engine.resourceManager
    .load<Texture2D>({
      url: "https://mdn.alipayobjects.com/huamei_jvf0dp/afts/img/A*nvhjTrdxAKEAAAAAAAAAAAAADleLAQ/original",
      type: AssetType.Texture2D,
    })
    .then((texture: Texture2D) => {
      background.mode = BackgroundMode.Texture;
      background.texture = texture;
      background.textureFillMode = BackgroundTextureFillMode.Fill;
    });

  engine.run();
});

[codecov]

Codecov Report

Patch coverage: 87.50% and project coverage change: +0.14% 🎉

Comparison is base (129e06e) 65.08% compared to head (f1245f7) 65.22%.
Report is 1 commits behind head on main.

❗ Current head f1245f7 differs from pull request most recent head e40908d. Consider uploading reports for the commit e40908d to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1784      +/-   ##
==========================================
+ Coverage   65.08%   65.22%   +0.14%     
==========================================
  Files         473      473              
  Lines       23641    23641              
  Branches     3362     3362              
==========================================
+ Hits        15386    15420      +34     
+ Misses       7049     7021      -28     
+ Partials     1206     1200       -6     

Files Changed	Coverage Δ
packages/core/src/Background.ts	77.63% <87.50%> (+18.42%)	⬆️

... and 5 files with indirect coverage changes

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