Unit tests that aim to verify the behavior and correctness of the sampling pipeline under various conditions

[csharpconsultant]

This pull request adds several unit tests to the LlamaSharp library's SamplingTests.cs file. The added tests aim to verify the behavior and correctness of the sampling pipeline under various conditions. The tests include:

SamplingWithTopK:

This test checks the behavior of the LLamaSamplerChainHandle when using different TopK values during sampling.

Ensures the sampled tokens and resulting text differ when using TopK=5 and TopK=50.

FrequencyPenalty_ThrowsException_WhenValueIsLessThanMinusTwo:

Verifies that an ArgumentOutOfRangeException is thrown when the frequency penalty is less than -2.

FrequencyPenalty_ThrowsException_WhenValueIsGreaterThanTwo:

Verifies that an ArgumentOutOfRangeException is thrown when the frequency penalty exceeds 2.

PresencePenalty_ThrowsException_WhenValueIsLessThanMinusTwo:

Verifies that an ArgumentOutOfRangeException is thrown when the presence penalty is less than -2.

PresencePenalty_ThrowsException_WhenValueIsGreaterThanTwo:

Verifies that an ArgumentOutOfRangeException is thrown when the presence penalty exceeds 2.

DefaultValues_AreSetCorrectly:

Verifies that the default values in the DefaultSamplingPipeline are set correctly.

Seed_HasLowProbabilityOfCollision:

This test verifies that the DefaultSamplingPipeline generates seeds with a low collision probability.

Seed_IsInitializedWithSpecificValue:

Verifies that the pipeline seed can be initialized with a specific value.

SetMinKeep:

Tests setting the MinKeep property to a specific value.

GetMinKeepDefault:

Verifies that the default value of the MinKeep property is set correctly.

[csharpconsultant]

I made the following updates:

Removed the non-deterministic sampling with temperature test.
Made the TopK test deterministic.
Removed the uint seed range test that would always pass.
Added a test to verify that the DefaultSamplingPipeline generates seeds with a low collision probability.