test(logback): [Sample Tests 3] Move the logback system test into the module

[runningcode]

PR Stack (Sample Tests)

• test: [Sample Tests 1] Add an in-process MockSentryServer #6266 (base: main)
• test: [Sample Tests 2] Share the system-test envelope matchers #6267 (base: test: [Sample Tests 1] Add an in-process MockSentryServer #6266)
• test(logback): [Sample Tests 3] Move the logback system test into the module #6268 (base: test: [Sample Tests 2] Share the system-test envelope matchers #6267)
• test(otel): [Sample Tests 4] Add a smoke test for the built agent #6269 (base: test: [Sample Tests 2] Share the system-test envelope matchers #6267)
• test(otel): [Sample Tests 5] Test a Spring Boot app under the agent #6271 (base: test(otel): [Sample Tests 4] Add a smoke test for the built agent #6269)

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📜 Description

Replaces sentry-samples-logback's system test with SentryAppenderIntegrationTest in sentry-logback. The new test:

• configures a fresh LoggerContext from an XML file. The file has a non-default name so logback's auto-configuration ignores it, and the DSN is substituted from a context property;
• logs the same sequence the sample's Main does;
• asserts events, breadcrumbs, feature flags and logs on MockSentryServer;
• also checks that the XML contextTag reaches the event as a tag, which the old test didn't.

The sample has no tests left, so this PR also removes:

• its system-test wiring and test dependencies;
• its Kotlin plugin, which only the tests used;
• its entries in system-tests-backend.yml and in the runner's module list.

💡 Motivation and Context

Until now, only the sample system test covered the appender's XML binding. That test needed the Python runner and a shadow JAR, and it ran in a non-blocking CI job. It now runs in about 3s as part of :sentry-logback:test.

💚 How did you test it?

• :sentry-logback:check passes.
• Temporarily broke an attribute assertion to confirm the test fails, with a clear Truth message.
• :sentry-samples:sentry-samples-logback:build still builds the sample's shadow JAR.

📝 Checklist

• I added GH Issue ID & Linear ID
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.
• Public API changes reviewed by another Mobile SDK team member or implemented according to the develop docs spec.

🔮 Next steps

The log4j2 and JUL console samples follow the same pattern.

#skip-changelog

[sentry]

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.61.0 (1)	release

⚙️ sentry-android Build Distribution Settings