build: removing unnecessary maven-compiler-plugin configuration

[suztomo]

The maven-compiler-plugin configuration is already defined in
the shared config pom.xml. This project does not need to declare
the plugin and its configuration.
https://github.com/googleapis/java-shared-config/blob/778a547a09de71dbf9e5a42b155f12d15c319864/pom.xml#L738

[suztomo]

It failed.

Error:  Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.11.0:compile (default-compile) on project google-cloud-pubsub: Compilation failure
Error:  /home/runner/work/java-pubsub/java-pubsub/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/SubscriberStats.java:[57,41] package AutoValue_SubscriberStats does not exist
Error:  -> [Help 1]

[suztomo]

The shared config has a strange setup to check EnableAutoValue.txt file.

    <profile>
      <id>autovalue-java8</id>
      <activation>
        <jdk>[1.8,)</jdk>
        <file>
          <exists>${basedir}/EnableAutoValue.txt</exists>
        </file>
      </activation>
      <build>
        <plugins>
          <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
              <annotationProcessorPaths>
                <path>
                  <groupId>com.google.auto.value</groupId>
                  <artifactId>auto-value</artifactId>
                  <version>${auto-value-annotation.version}</version>
                </path>
...

The profile is then only active if all conditions are met

https://maven.apache.org/guides/introduction/introduction-to-profiles.html#multiple-conditions

[suztomo]

It failed again. https://github.com/googleapis/java-pubsub/actions/runs/6420127119/job/17431538139?pr=1761 Now I'm moving the file to google-cloud-pubsub directory.