fix: resolver ty mismatch in the assign statement with the schema type annotation

[Peefy]

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

• N
• Y

fix: #325

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

Refactor

• kclvm/sema/src/resolver/global.rs
• kclvm/sema/src/resolver/node.rs

Fix

• must_assignable_to call at kclvm/sema/src/resolver/node.rs

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/var_type_annotation/type_fail_10/main.k
• test/grammar/types/var_type_annotation/type_fail_11/main.k
• test/grammar/types/var_type_annotation/type_fail_12/main.k

6. Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[coveralls]

Pull Request Test Coverage Report for Build 3945569232

• 9 of 9 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-29.1%) to 61.467%

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Totals
Change from base Build 3939148325:	-29.1%
Covered Lines:	21431
Relevant Lines:	34866

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💛 - Coveralls

[zong-zhe]

LGTM