[Bug] vchart widget updateSpec is set to the default size

[pairone]

Version

1.2.0

Link to Minimal Reproduction

null

Steps to Reproduce

小程序里没有container，document.getElement拿不到canvas，就走了默认的宽高逻辑

Current Behavior

20230817-151726.mp4

Expected Behavior

No change in size after updateSpec

Environment

- OS:
- Browser:
- Framework:

Any additional comments?

No response