feat: enhance config attribute type inference through the config attribute type map.

[Peefy]

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• Y

re #635

feat: enhance config attribute type inference through the config attribute type map.

metadata = {
    name = "app"
    labels.app = "app"
}
labels: {str:str} = metadata.labels

Before this PR, the type of metadata.labels will be inferred as a {str:str}|str type. In fact, we can derive more precise types, and this PR solves this problem. The more information is in #635

2. What is the scope of this PR (e.g. component or file name):

The kcl sematic model crate

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Other

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

• Unit test
• Integration test
• Benchmark (add benchmark stats below)
• Manual test (add detailed scripts or steps below)
• Other

• test/grammar/types/union_ty/union_ty_11/main.k
• test/grammar/types/union_ty/union_ty_12/main.k

[zong-zhe]

LGTM

[He1pa]

LGTM