Update WithSpan tests

[jaydeluca]

Updates tests:

• Use waitAndAssertTraces instead of assertThat(testing.waitForTraces(1))
• Use span.withNoParent() instead of span.hasParentSpanId(SpanId.getInvalid())
• Use hasAttributesSatisfyingExactly instead of attributes -> assertThat(attributes).containsOnly(...
• Use static imports where possible
• Remove some unnecessary throws Exception