fix(series): avoid NPE caused by seriesData.getLinkedData

[plainheart]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

getLinkedData might not exist in some series data, which causes an NPE. This PR adds a non-null check to avoid this error.

Error: TypeError: data.getLinkedData is not a function at LinesSeriesModel.SeriesModel.getData

See this online demo

Fixed issues

• Resolves [Bug] series同时使用type: 'graph'，type: 'lines'，series ——type'graph'中配置emphasis: { focus: 'adjacency'}，鼠标hover就报错，开发版本中会导致页面崩溃 #19900

Details

Before: What was the problem?

Chart rendered but thrown an error.

After: How does it behave after the fixing?

Chart rendered without error.

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

See the 4th case in test/graph-case.html.

Others

Merging options

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

Other information

[echarts-bot]

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[github-actions]

The changes brought by this PR can be previewed at: https://echarts.apache.org/examples/editor?version=PR-19901@ea0da63

[echarts-bot]

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

[tab91622]

@plainheart Great, thank you！大佬