Fix v3 CI path filter case and remove stale files entry (#4465)

## Description

Two small cleanups:

- The path filter in `rngh-api-v3.yml` pointed at `API_V3.test.tsx`, but
the file is `api_v3.test.tsx` and GitHub path filters are
case-sensitive, so a PR touching only the v3 test suite never triggered
the workflow. The mismatch has been there since the workflow was added
in #3838. Also lowercased the pattern in the `yarn test` step to match
the file literally (it worked before only because jest matches patterns
case-insensitively).
- Removed `android/common/src/main/java/` from `files` in `package.json`
- the directory was deleted in #3544, npm silently ignores the unmatched
entry.

## Test plan

- `npx jest --listTests RelationsTraversal api_v3` still selects both
test files.