Update plugin spotless to v8.9.0

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
com.diffplug.spotless	8.0.0 → 8.9.0

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Configuration

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[renovate]

⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

• any of the package files in this branch needs updating, or
• the branch becomes conflicted, or
• you click the rebase/retry checkbox if found above, or
• you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: gradle/libs.versions.toml

Command failed: ./gradlew -Dorg.gradle.jvmargs=-Xms512m -Xmx512m --console=plain --dependency-verification lenient -q properties

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring project ':buildLogic:convention'.
> Could not resolve all artifacts for configuration 'classpath'.
   > Could not resolve org.jetbrains.kotlin:kotlin-gradle-plugin:2.3.0.
     Required by:
         buildscript of project ':buildLogic:convention' > org.jetbrains.kotlin.jvm:org.jetbrains.kotlin.jvm.gradle.plugin:2.3.0
      > Could not resolve org.jetbrains.kotlin:kotlin-gradle-plugin:2.3.0.
         > Could not parse POM https://plugins.gradle.org/m2/org/jetbrains/kotlin/kotlin-gradle-plugin/2.3.0/kotlin-gradle-plugin-2.3.0.pom
            > Could not resolve org.jetbrains.kotlin:kotlin-gradle-plugins-bom:2.3.0.
               > Could not resolve org.jetbrains.kotlin:kotlin-gradle-plugins-bom:2.3.0.
                  > Could not get resource 'https://plugins.gradle.org/m2/org/jetbrains/kotlin/kotlin-gradle-plugins-bom/2.3.0/kotlin-gradle-plugins-bom-2.3.0.pom'.
                     > Could not GET 'https://repo.maven.apache.org/maven2/org/jetbrains/kotlin/kotlin-gradle-plugins-bom/2.3.0/kotlin-gradle-plugins-bom-2.3.0.pom'. Received status code 429 from server: Too Many Requests

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to generate a Build Scan (powered by Develocity).
> Get more help at https://help.gradle.org.

BUILD FAILED in 47s