[Feature] Disable triggering tooltip for items disabled by visualMap

[JuliaCwynar]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

Adds tooltip.trigger option for active items:
tooltip.trigger = 'activeItem'
It enables showing tooltip only for items that are active (not modified by visualMap) when visualMap is present. At the same time it doesn't modify current logic implemented for `tooltip.trigger = 'item', which is a default option.

Fixed issues

• [Feature] Disable triggering tooltip for items disabled by visualMap #21053

Details

Before: What was the problem?

If item is disabled by visualMap, tooltip is still being shown, even if there is no node.

After: How does it behave after the fixing?

If user sets tooltip.trigger = 'activeItem', if item is disabled by visualMap, it won't trigger tooltip.

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