EmbeddingUtils.toPrimitive(List<Float> floats) is suboptimal and can be twice as fast

[wpanas]

Bug description
A clear and concise description of what the bug is about.

EmbeddingUtils.toPrimitive(List<Float> floats) unnecessarily converts List<Float> to Float[] that is later converted to float[]. I achieved twice as much operations per seconds by directly converting from List<Float> to float[]

Benchmark                    Mode  Cnt        Score       Error  Units
MyBenchmark.toPrimitive     thrpt    5  1671525,687 ± 19770,013  ops/s
MyBenchmark.toPrimitiveNew  thrpt    5  3107477,889 ± 29323,152  ops/s

Environment
Please provide as many details as possible: Spring AI version, Java version, which vector store you use if any, etc

• Spring AI 1.0.1
• I benchmarked it on Java 21

Steps to reproduce
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• Run benchmark with long List<Float>. I created lists of 768 floats, but text-embedding-3-large can be vector of 3072 floats.

Expected behavior
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I'll create a PR for fixing it and I'd like you to merge it 😄

Minimal Complete Reproducible example
Please provide a failing test or a minimal complete verifiable example that reproduces the issue.
Bug reports that are reproducible will take priority in resolution over reports that are not reproducible.

[wpanas]

PR is ready #4347

[ilayaperumalg]

@wpanas Thanks for the PR improving the performance and benchmarking the result.