Fix tests

[lein3000zzz]

Fixed a conflict where the global ONNX Runtime environment was persisting between test cases after my #2 (sorry, i didn't foresee that - my original goal was to make the model work). Added DestroyOrtEnv() to allow manual lifecycle management of the ORT environment, ensuring tests can run in isolation without "already initialized" errors.

=== RUN   TestSingleSentenceEmbedding
--- PASS: TestSingleSentenceEmbedding (0.27s)
=== RUN   TestBatchEmbedding
--- PASS: TestBatchEmbedding (0.24s)
=== RUN   TestConsistentEmbeddingForSameSentence
--- PASS: TestConsistentEmbeddingForSameSentence (0.22s)
=== RUN   TestSingleVsBatchConsistency
--- PASS: TestSingleVsBatchConsistency (0.21s)
=== RUN   TestEmptyBatch
--- PASS: TestEmptyBatch (0.20s)
PASS