Removed quotation of nerdctl_extra_flags. (#8695)

The quotations in the variable nerdctl_extra_flags are not required for the `nerdctl_image_pull_command` and throw the following error when executing the cluster-playbook with `container_insecure_registries` set:
        unknown flag: --insecure-registry\\\"
This happens as the complete nerdctl_image_pull_command string variable gets split into an array string for the cmd task. The escaped quotation doesn't get escaped properly and is added to the cmd-string array as part of the command. This leads to a wrong written insecure-registry flag, which throws this error.

roles/download/defaults/main.yml

@@ -49,7 +49,7 @@ download_delegate: "{% if download_localhost %}localhost{% else %}{{ groups['kub
 docker_image_pull_command: "{{ docker_bin_dir }}/docker pull"
 docker_image_info_command: "{{ docker_bin_dir }}/docker images -q | xargs -i {{ '{{' }} docker_bin_dir }}/docker inspect -f {% raw %}'{{ '{{' }} if .RepoTags }}{{ '{{' }} join .RepoTags \",\" }}{{ '{{' }} end }}{{ '{{' }} if .RepoDigests }},{{ '{{' }} join .RepoDigests \",\" }}{{ '{{' }} end }}' {% endraw %} {} | tr '\n' ','"
 nerdctl_image_info_command: "{{ bin_dir }}/nerdctl -n k8s.io images --format '{% raw %}{{ '{{' }} .Repository {{ '}}' }}:{{ '{{' }} .Tag {{ '}}' }}{% endraw %}' 2>/dev/null | grep -v ^:$ | tr '\n' ','"
-nerdctl_image_pull_command: "{{ bin_dir }}/nerdctl -n k8s.io pull --quiet{{ nerdctl_extra_flags }}"
+nerdctl_image_pull_command: "{{ bin_dir }}/nerdctl -n k8s.io pull --quiet {{ nerdctl_extra_flags }}"
 crictl_image_info_command: "{{ bin_dir }}/crictl images --verbose | awk -F ': ' '/RepoTags|RepoDigests/ {print $2}' | tr '\n' ','"
 crictl_image_pull_command: "{{ bin_dir }}/crictl pull"
 
@@ -65,7 +65,7 @@ image_info_command_on_localhost: "{{ lookup('vars', image_command_tool_on_localh
 image_arch: "{{host_architecture | default('amd64')}}"
 
 # Nerdctl insecure flag set
-nerdctl_extra_flags: '{%- if containerd_insecure_registries is defined and containerd_insecure_registries|length>0 -%}\" --insecure-registry\"{%- else -%}{%- endif -%}'
+nerdctl_extra_flags: '{%- if containerd_insecure_registries is defined and containerd_insecure_registries|length>0 -%}--insecure-registry{%- else -%}{%- endif -%}'
 
 # Versions
 kubeadm_version: "{{ kube_version }}"