style: simplify get value

[hchlq]

Before submitting a pull request, please make sure the following is done...

• [x] Ensure the pull request title and commit message follow the Commit Specific in English.
• [x] Fork the repo and create your branch from master or formily_next.
• [ ] If you've added code that should be tested, add tests!
• [ ] If you've changed APIs, update the documentation.
• [ ] Ensure the test suite passes (npm test).
• [ ] Make sure your code lints (npm run lint) - we've done our best to make sure these rules match our internal linting guidelines.

Please do not delete the above content

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What have you changed?

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (b9ab509) 96.59% compared to head (899c145) 96.59%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## formily_next #3887 +/- ## ============================================= Coverage 96.59% 96.59% ============================================= Files 152 152 Lines 6695 6695 Branches 1869 1869 ============================================= Hits 6467 6467 Misses 200 200 Partials 28 28 ``` | [Impacted Files](https://app.codecov.io/gh/alibaba/formily/pull/3887?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=alibaba) | Coverage Δ | | |---|---|---| | [packages/validator/src/template.ts](https://app.codecov.io/gh/alibaba/formily/pull/3887?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=alibaba#diff-cGFja2FnZXMvdmFsaWRhdG9yL3NyYy90ZW1wbGF0ZS50cw==) | `100.00% <100.00%> (ø)` | |

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