Add ability to create zstd compressor with compression level

[DracoLi]

Why this should be merged

Blockdb supports zstd compression for blocks, but it needs a non-default compression level (default is level 5).

How this works

This PR adds a NewZstdCompressorWithLevel function to enable zstd compression with a custom level.

How this was tested

Unit tests and blockdb tests in #4201

Need to be documented in RELEASES.md?

Don't think so

[Copilot]

Pull Request Overview

This PR adds the ability to create a zstd compressor with a custom compression level to support blockdb's requirement for non-default compression levels.

• Introduces NewZstdCompressorWithLevel function that accepts a compression level parameter
• Refactors existing NewZstdCompressor to use the new function with default compression level
• Updates the compressor to use zstd.CompressLevel instead of zstd.Compress

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
utils/compression/zstd_compressor.go	Adds new constructor with level parameter and updates compression logic
utils/compression/compressor_test.go	Adds test coverage for the new constructor function

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