feat(type): export ECElementEvent for TypeScript

[keita-determined]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

Export ECElementEvent for Typescript

Fixed issues

#17888

Details

Before: What was the problem?

Couldn't export ECElementEvent

After: How does it behave after the fixing?

ECElementEvent should be exportable by import { ECElementEvent } from "echarts";

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

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.

[plainheart]

Thank you! :)

[echarts-bot]

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