Manual changes required for library removals.

[mpeddada1]

The original PR only deleted the .java classes but still kept the pom.xml files and the java-game-servers module. Created a manual commit to:

• Delete the java-game-servers module.
• Remove com.google.cloud:google-cloud-game-servers-bom from the <dependencies> block in gapic-libraries-bom/pom.xml.

Originally posted by @mpeddada1 in https://github.com/googleapis/google-cloud-java/issues/9787#issuecomment-1714163758

While this change was handled manually for java-game-servers, there may be more cases in the future where the removal APIs requires these manual changes by the team. There is an opportunity to automate this.