Remove the BuildListener when support for gradleVersion < 8.6 is dropped

[crogoz]

What happened?

We are using a BuildListener for gradleVersion < 8.6 here whose buildFinished is deprecated.

What did you want to happen?

When we drop support for gradleVersion < 8.6, we can remove the buildListener, remove the AutoClosable implementation and report the compile failures in:

gradle-failure-reports/gradle-failure-reports/src/main/java/com/palantir/gradle/failurereports/BuildFailureReporter.java

Line 57 in 34ae3fe

// TODO(crogoz): use compileFailuresService to report the errors once everything is on gradle >= 8.6