Updating score assertions to use close_to instead of match for linear_retriever yml tests

[pmpailis]

This PR changes the score validation in linear retriever yaml tests from match to close_to to avoid arithmetic errors like the following:

java.lang.AssertionError: Failure at [linear/10_linear_retriever:319]: field [hits.hits.3._score] doesn't match the expected value
Expected: <1.2>
     but: was <1.2000000476837158>

Closes #128774

[elasticsearchmachine]

Pinging @elastic/es-search-relevance (Team:Search Relevance)

[pmpailis]

run elasticsearch-ci/part-4

[Copilot]

Pull Request Overview

This PR refactors the linear retriever YAML tests to use close_to assertions for floating-point scores (with a small tolerance) and re-enables the previously muted normalization test.

• Switch hard match checks on hits.hits.*._score to close_to with error: 0.001
• Remove the mute entry for the should normalize initial scores with l2_norm test

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
x-pack/plugin/rank-rrf/src/yamlRestTest/resources/rest-api-spec/test/linear/10_linear_retriever.yml	Updated all _score assertions to use close_to with a ±0.001 margin
muted-tests.yml	Unmuted the linear retriever normalization test by removing its entry

Comments suppressed due to low confidence (1)

x-pack/plugin/rank-rrf/src/yamlRestTest/resources/rest-api-spec/test/linear/10_linear_retriever.yml:265

• [nitpick] Inline map spacing is inconsistent here; consider removing the extra space before the closing brace to match the formatting of other close_to entries.

-  - close_to: { hits.hits.3._score: { value: 0.0, error: 0.001 } }

[benwtrent]

IEEE 754 strikes again. I hate floating point.