[sdk-platform-java] investigate fmt-maven-plugin upgrade error

fmt-maven-plugin upgrade to 2.13 is failing on error for ci/lint and ci/showcase, but pass for other ci checks.
see https://github.com/googleapis/sdk-platform-java/pull/3544#issuecomment-2576147488

Found this old attempt to upgrade failing with Java incompatible: https://github.com/googleapis/sdk-platform-java/pull/941 unsure if related.
One other clue is https://github.com/googleapis/sdk-platform-java/pull/2533, shows `com.google.googlejavaformat:google-java-format` version in project is not uniformed. and google-java-format 1.14 requires java 11 (ref: https://github.com/googleapis/google-cloud-java/issues/12529)