[improve][build] Upgrade Gradle to 9.8.0 and update plugins - #26752

Motivation

Keep Pulsar's Gradle build and plugins current, and address the build deprecations exposed by Gradle 9.8.0. The RAT plugin update removes its use of the deprecated ReportingExtension.file API.

Modifications

• Upgrade Gradle from 9.7.1 to 9.8.0, regenerate the wrapper, and update the distribution checksum while preserving the download retry settings.
• Upgrade RAT 0.8.1 → 0.11.0, Spotless 8.10.0 → 8.10.3, GraalVM native-build-tools 1.1.9 → 1.1.14, and the versions plugin 0.61.0 → 0.64.0.
• Upgrade the Swagger plugin and Jakarta libraries together from 2.2.53 to 2.2.55, updating the server and shell license inventories. The Swagger resolver retains the pinned EE10 APIs and Jackson 2.21.6.

The Protobuf plugin remains at its latest published version, 0.10.0. It still emits a Configuration.setVisible deprecation warning; the fix is merged in google/protobuf-gradle-plugin#816 but is not yet released.

Verifying this change

Passed locally:

• ./gradlew help assemble sanityCheck checkBinaryLicense --no-configure-on-demand --configuration-cache --warning-mode=all --console=plain (sanityCheck includes the source/license/style checks in quickCheck).
• ./gradlew dependencyUpdates :pulsar-broker:generateOpenApiSpecs --no-configuration-cache --no-configure-on-demand --no-parallel --no-build-cache --warning-mode=all --console=plain.
• Swagger dependency graph inspection and configuration-cache reuse.
• Wrapper JAR checksum verification against Gradle's published checksum; the wrapper verified the distribution checksum during download.

Tests and native-image compilation were not run. Earlier full compilation emitted Java source/JDK warnings; the remaining Gradle API deprecation is the Protobuf warning described above.

• Make sure that the change passes the CI checks.

Does this pull request potentially affect one of the following parts:

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment