Skip `none` system_modules from module_bp_java_deps.json

`none` is not a soong module, and can be skipped.

Test: go test ./java
Test: verified that `none` no longer appears in deps of
`android-non-updatable.stubs.from-text`

Bug: 373837953
Change-Id: I3bf60b762a52f1b236dde8dd020aa291697939b2