GH-49144: [R][CI] Get rid of unused CentOS CI job (#49239)

### Rationale for this change

Remove unused CI jobs

### What changes are included in this PR?

Remove unused CI jobs - CentOS

### Are these changes tested?

No

### Are there any user-facing changes?

No
* GitHub Issue: #49144

Authored-by: Nic Crane <thisisnic@gmail.com>
Signed-off-by: Nic Crane <thisisnic@gmail.com>

Author: thisisnic

dev/tasks/r/github.packages.yml

@@ -352,41 +352,6 @@ jobs:
           Rscript -e '
           {{  macros.github_test_r_src_pkg()|indent(8) }}
           '
-      - name: Upload binary artifact
-        if: matrix.config.devtoolset
-        uses: actions/upload-artifact@v4
-        with:
-          name: r-pkg_centos7
-          path: arrow_*
-
-  test-centos-binary:
-    # arrow binary package not on ppm currently see #37922
-    if: false
-    needs: test-linux-binary
-    runs-on: ubuntu-latest
-    container: "posit/r-base:4.2-centos7"
-    steps:
-      - uses: actions/download-artifact@v4
-        with:
-          name: r-pkg_centos7
-      - name: Install DTS Package
-        shell: Rscript {0}
-        run: |
-          pkg <- list.files(pattern = "arrow_*")
-          if(length(pkg) > 1) {
-            pkg <- pkg[[1]]
-            warning("Multiple packages found! Using first one.")
-          }
-
-          # Install dependencies from RSPM
-          install.packages("arrow", repos = "https://packagemanager.rstudio.com/all/__linux__/centos7/latest")
-          remove.packages("arrow")
-
-          install.packages(pkg)
-          library(arrow)
-          read_parquet(system.file("v0.7.1.parquet", package = "arrow"))
-          print(arrow_info())
-
   test-source:
     needs: source
     name: Test {{ '${{ matrix.platform.name }}' }} source build