Update samplers module to follow style guide

[Copilot]

This PR updates the samplers module to align with all recommendations in the style guide, making minimal changes as requested.

Changes Made

Collection API improvements:

• Changed parentLinks.size() > 0 to !parentLinks.isEmpty() in LinksBasedSampler for better readability

Static imports:

• Added static import for java.util.Objects.hash in SamplingRule class

Class visibility:

• Added final keyword to LinksParentAlwaysOnSamplerProvider (public classes should be final per style guide)

SPI registration:

• Added @AutoService annotations to SPI implementations (LinksParentAlwaysOnSamplerProvider and RuleBasedRoutingSamplerComponentProvider)
• Added AutoService dependencies to build.gradle.kts
• Removed manual META-INF/services files (AutoService generates them automatically)
• Added @SuppressWarnings("rawtypes") to handle AutoService warning for generic ComponentProvider

All changes maintain backward compatibility and follow the principle of minimal necessary modifications. The module builds successfully and all tests pass.

Fixes #411.

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