fix: tooltip formatter callback for connected charts. close #21307

[PPRAMANIK62]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

Fixed tooltip formatter for connected charts stuck in loading state

Fixed issues

Details

Before: What was the problem?

1. Hover over one chart
2. Tooltip is shown and value changes from Loading to Value: ${value}
3. Connected chart tooltip is shown but it is stuck in Loading ❌

After: How does it behave after the fixing?

1. Hover over one chart
2. Tooltip is shown and value changes from Loading to Value: ${value}
3. Connected chart tooltip is shown and value changes from Loading to Value: ${value}✅

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]

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