feat(sankey): add itemStyle.borderRadius option for sankey series

[deftliang]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

Add sankey chart itemStyle.borderRadius support.

Fixed issues

fix: #19750

Details

Before: What was the problem?

Sankey chart itemStyle.borderRadius is not support.

After: How does it behave after the fixing?

Support border Radius configuration

Document Info

One of the following should be checked.

• This PR doesn't relate to document changes
• The document should be updated later
• The document changes have been made in doc(sankey): add doc for sankey itemStyle.borderRadius echarts-doc#393

Misc

ZRender Changes

• This PR depends on ZRender changes (ecomfe/zrender#xxx).

Related test cases or examples to use the new APIs

N.A.

Others

Merging options

• Please squash the commits into a single one when merging.

Other information

[echarts-bot]

Thanks for your contribution!
The community will review it ASAP. In the meanwhile, please checkout the coding standard and Wiki about How to make a pull request.

⚠️ MISSING DOCUMENT INFO: Please make sure one of the document options are checked in this PR's description. Search "Document Info" in the description of this PR. This should be done either by the author or the reviewers of the PR.

[echarts-bot]

Document changes are required in this PR. Please also make a PR to apache/echarts-doc for document changes and update the issue id in the PR description. When the doc PR is merged, the maintainers will remove the PR: awaiting doc label.

[echarts-bot]

Congratulations! Your PR has been merged. Thanks for your contribution! 👍

[Ovilia]

Thanks for your contribution. Do you mind making a pull request to the doc at dev branch?

[deftliang]

Thanks for your contribution. Do you mind making a pull request to the doc at dev branch?

I'm glad to help! I have created a pull request. apache/echarts-doc#393