test(server-utils): Remove hapi unit test that replicated SDK async-context logic (#22100)

Removes the hapi unit test that stubbed the SDK's async context strategy
to drive spans, which replicated SDK internals in the test layer. Per
the review thread in #21885, we rely on the integration tests instead.

The orchestrion path is covered by the `hapi` node integration suite.
`hapi-utils.test.ts` stays (pure metadata formatting, no async-context
stubbing). The remaining unit-only assertions checked internal
implementation details (setup only wrapping once when called twice, no
span without an active span, accepting the ext handler as a tuple or an
object) rather than the spans a user actually sees, so there was nothing
meaningful to move into an integration test.

Ref:
#21885 (comment)

Co-authored-by: Opus 4.8 <noreply@anthropic.com>

Author: andreiborza