refactor: simplify json_like trait

[meskill]

Summary:
Simplify JsonLike associated type constraints according to TODO in the code. This is doable after serde_json_borrow update https://github.com/PSeitz/serde_json_borrow/pull/19

Build & Testing:

• [ ] I ran cargo test successfully.
• [ ] I have run ./lint.sh --mode=fix to fix all linting issues raised by ./lint.sh --mode=check.

Checklist:

• [ ] I have added relevant unit & integration tests.
• [ ] I have updated the documentation accordingly.
• [ ] I have performed a self-review of my code.
• [ ] PR follows the naming convention of <type>(<optional scope>): <title>

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 57.89474% with 8 lines in your changes missing coverage. Please review.

Project coverage is 87.13%. Comparing base (d473af2) to head (80b9490). Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/core/json/serde.rs	0.00%	5 Missing :warning:
src/core/json/borrow.rs	60.00%	2 Missing :warning:
src/core/json/graphql.rs	80.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2780 +/- ## ======================================= Coverage 87.13% 87.13% ======================================= Files 254 254 Lines 25144 25144 ======================================= Hits 21909 21909 Misses 3235 3235 ```

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