Add a forbidModuleImports step similar to existing forbidWildcardImports

[tbroyer]

Java 25 adds a new import module syntax. It would be great to be able to forbid it in the same way we can forbid wildcard imports.

Related:

• Support Module Import Declarations (JEP 476, JDK 23) google/google-java-format#1213
• Update Java Style Guide to latest google/styleguide#946