[GH] (texera/main): Workflow run "Build and push images" is working again!

[GitBox <gi...@apache.org>]

The GitHub Actions job "Build and push images" on texera.git/main has succeeded.
Run started by GitHub user bobbai00 (triggered by bobbai00).

Head commit for run:
51fb0b8acb604867e3b786f293d447f88c50522d / Jiadong Bai <43...@users.noreply.github.com>
chore: drop R support flags from Dockerfiles and CI workflow (#4124)

### What changes were proposed in this PR?

This PR removes the `WITH_R_SUPPORT` build argument and all R-related
installation logic from the Docker build configuration:

1. **Dockerfiles** (`computing-unit-master.dockerfile` and
`computing-unit-worker.dockerfile`):
   - Removed `ARG WITH_R_SUPPORT` build argument
   - Removed conditional R runtime dependencies installation
   - Removed R compilation and installation steps (R 4.3.3)
   - Removed R packages installation (arrow, coro, dplyr)
   - Removed `LD_LIBRARY_PATH` environment variable for R libraries
   - Removed `r-requirements.txt` copy in worker dockerfile
   - Simplified to Python-only dependencies

2. **GitHub Actions Workflow**
(`.github/workflows/build-and-push-images.yml`):
   - Removed `with_r_support` workflow input parameter
   - Removed `with_r_support` from job outputs and parameter passing
- Removed `WITH_R_SUPPORT` build args from both AMD64 and ARM64 build
steps
   - Removed R Support from build summary

### Any related issues, documentation, discussions?

Related to #4090

### How was this PR tested?

Verified Dockerfile & CI yml syntax are valid

### Was this PR authored or co-authored using generative AI tooling?

Generated-by: Claude Sonnet 4.5 (claude-sonnet-4-5-20250929) via Claude
Code CLI

Report URL: https://github.com/apache/texera/actions/runs/20044591223

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