refactor: Remove TransactionSnapshot structure

[xxuejie]

As of now, TransactionSnapshot and TransactionState from ckb-script package are exactly the same. There is no need to keep them both.

What problem does this PR solve?

Issue Number: close #xxx

Problem Summary:

What is changed and how it works?

Proposal: xxx

What's Changed:

Related changes

• PR to update owner/repo:
• Need to cherry-pick to the release branch

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code ci-runs-only: [ quick_checks,linters ]

Side effects

• Performance regression
• Breaking backward compatibility

Release note

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