fix: Android span e2e tests (#397)

## Summary

Fixes and removes ignore on span e2e tests. Flag Eval on the launch was
intervening with tests

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Low risk: changes are limited to the Android E2E test harness and test
annotations, with no impact on production SDK logic beyond skipping a
test-only span trigger during tests.
> 
> **Overview**
> Fixes flaky Android span E2E tests by preventing `BaseApplication`
from running `flagEvaluation()` during test runs (gated on `testUrl ==
null`), avoiding extra spans that interfered with assertions.
> 
> Re-enables previously ignored span-related E2E coverage by removing
`@Ignore` from several trace/export and sampling tests in
`DisablingConfigOptionsE2ETest` and `SamplingE2ETest`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
618e2b1. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: abelonogov-ld

e2e/android/app/src/test/java/com/example/androidobservability/DisablingConfigOptionsE2ETest.kt

@@ -73,7 +73,6 @@ class DisablingConfigOptionsE2ETest {
 
 
     @Test
-    @Ignore
     fun `Spans should NOT be exported when TracesApi is disabled`() {
         application.observabilityOptions = getOptionsAllEnabled().copy(tracesApi = ObservabilityOptions.TracesApi.disabled())
         application.initForTest()
@@ -90,7 +89,6 @@ class DisablingConfigOptionsE2ETest {
     }
 
     @Test
-    @Ignore
     fun `Spans should NOT be exported when TracesApi does not include spans`() {
         application.observabilityOptions = getOptionsAllEnabled().copy(
             tracesApi = ObservabilityOptions.TracesApi(includeSpans = false)
@@ -152,7 +150,6 @@ class DisablingConfigOptionsE2ETest {
     }
 
     @Test
-    @Ignore
     fun `Errors should NOT be exported when TracesApi does not include errors`() {
         application.observabilityOptions = getOptionsAllEnabled().copy(
             tracesApi = ObservabilityOptions.TracesApi(includeErrors = false)
@@ -171,7 +168,6 @@ class DisablingConfigOptionsE2ETest {
     }
 
     @Test
-    @Ignore
     fun `Errors should be exported as spans when TracesApi include errors but not spans`() {
         application.observabilityOptions = getOptionsAllEnabled().copy(
             tracesApi = ObservabilityOptions.TracesApi(includeErrors = true, includeSpans = false)