fix(heatmap): fix heatmap label may overlap when dataZoom is enabled

[plainheart]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

When dataZoom is enabled in the heatmap series, the label will probably overlap when the corresponding data item is filtered.
This PR fixes this bug by judging if the X dimension & Y dimension is a number.

Fixed issues

• Resolves [Bug] When add the slider to the heat map the data will overlap #17844

Details

Before: What was the problem?

After: How does it behave after the fixing?

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

Please refer to the last case in test/heatmap.html.

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.

The pull request is marked to be PR: author is committer because you are a committer of this project.

[echarts-bot]

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