Revert EL8 Python bootstrap and Calico CI (#13596)

This reverts commit e19d1c9a55.

Allow further maintainer discussion without introducing additional changes.

Signed-off-by: Kay Yan <kay.yan@daocloud.io>

roles/bootstrap_os/tasks/centos.yml

@@ -1,42 +1,4 @@
 ---
-- name: Bootstrap Python
-  when: bootstrap_os_install_python
-  block:
-    - name: Check if Python bootstrap is needed
-      vars:
-        python_interpreter: "{{ lookup('config', 'INTERPRETER_PYTHON') | trim }}"
-        python_candidates: >-
-          {{ lookup('config', 'INTERPRETER_PYTHON_FALLBACK')
-             if python_interpreter in ['', 'auto', 'auto_silent'] else [python_interpreter] }}
-      raw: |
-        for python in {{ python_candidates | map('quote') | join(' ') }}; do
-          if command -v "$python" >/dev/null 2>&1; then
-            "$python" -c 'import sys; sys.exit(sys.version_info[:2] < (3, 9))'
-            exit $?
-          fi
-        done
-        exit 1
-      register: need_bootstrap
-      changed_when: false
-      failed_when: need_bootstrap.rc not in [0, 1]
-      check_mode: false
-
-    # Keep platform-python for the ansible-core DNF helper.
-    - name: Install Python 3.12
-      raw: >-
-        yum --assumeyes
-        {% if not skip_http_proxy_on_os_packages and http_proxy is defined %}
-        --setopt={{ ('proxy=' ~ http_proxy) | quote }}
-        {% endif %}
-        install python3.12
-      become: true
-      register: bootstrap_python
-      until: bootstrap_python is succeeded
-      retries: "{{ pkg_install_retries }}"
-      delay: "{{ retry_stagger | random + 3 }}"
-      timeout: "{{ pkg_install_timeout }}"
-      when: need_bootstrap.rc != 0
-
 - name: Gather host facts to get ansible_distribution_version ansible_distribution_major_version
   setup:
     gather_subset: '!all'
@@ -99,6 +61,8 @@
     - (ansible_facts['distribution_version'] | float) >= 7.6
     - (ansible_facts['distribution_version'] | float) < 9
 
+# CentOS ships with python installed
+
 - name: Check presence of fastestmirror.conf
   stat:
     path: /etc/yum/pluginconf.d/fastestmirror.conf