fix(lines): add symbols to lines series when polyline is set to true

[thenotrealagata]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

Add symbols to lines series when polyline is set to true, refactor symbol drawing functionality from the Line file.

Fixed issues

#19767

Details

Before: What was the problem?

When the polyline attribute was set to true in an option for a lines series, the symbols weren't rendered.

After: How does it behave after the fixing?

The symbols are rendered on a Polyline, utilising the same logic as when rendering the symbols on a Line.

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 apache/echarts-doc#xxx

Misc

ZRender Changes

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

Related test cases or examples to use the new APIs

New test case added to the lines-symbol test file.

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.