fix(sunburst): preserve data decal. close #18118

[rahul37wallst-sudo]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

Preserve sunburst data item decal overrides when ARIA decal generation is enabled.

Fixed issues

• [Bug] Sunburst decal override doesn't work: series-sunburst.data.itemStyle.decal #18118: series-sunburst.data.itemStyle.decal was overwritten by aria.decal.decals.

Details

Before: What was the problem?

When aria.decal.show was enabled for a sunburst series, the tree-specific ARIA decal helper assigned palette decals directly to each tree node.

Because sunburst ignores generic data item style processing, series.data[].itemStyle.decal was not preserved before ARIA decal assignment. As a result, a data item such as:

{
    name: 'Changed decal',
    value: 1,
    itemStyle: {
        decal: {
            symbol: 'none'
        }
    }
}

still rendered with the global ARIA decal, for example symbol: 'circle'.

After: How does it behave after the fixing?

The tree ARIA decal helper now reads a node's itemStyle.decal, merges it over the palette decal, and preserves explicit decal: 'none'.

This allows sunburst data items to override or disable the ARIA decal while keeping palette decals for items without an override.

A regression test was added for the sunburst + ARIA decal case.

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

Security Checking

• This PR uses security-sensitive Web APIs.

ZRender Changes

• This PR depends on ZRender changes (ecomfe/zrender#xxx).

Related test cases or examples to use the new APIs

test/ut/spec/series/sunburst.test.ts

Merging options

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

Other information

Validation run locally:

npx jest --config test/ut/jest.config.cjs --coverage=false --runInBand --runTestsByPath test/ut/spec/series/aria-columns-exclude.test.ts test/ut/spec/series/sunburst.test.ts
npx eslint src/chart/helper/enableAriaDecalForTree.ts test/ut/spec/series/sunburst.test.ts
npm run checktype
git diff --check