fix(gitlab): scope dns_servers detection to [containers] section

The previous grep/sed searched the whole file, so a dns_servers key
in any other section (e.g. [network]) would trigger a false-positive
check and replace the wrong key. Switch to awk that tracks whether the
current line is inside [containers] for both the existence check and
the in-place replacement.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: adrianriobo

pkg/integrations/gitlab/snippet-linux.sh

@@ -46,9 +46,16 @@ if [ -n "$_dns_servers" ]; then
         printf '[containers]\ndns_servers = [%s]\n' "$_toml_list" \
             | sudo tee /etc/containers/containers.conf > /dev/null
     elif grep -q '^\[containers\]' /etc/containers/containers.conf; then
-        if grep -q 'dns_servers' /etc/containers/containers.conf; then
-            sudo sed -i "s|^dns_servers.*|dns_servers = [${_toml_list}]|" \
-                /etc/containers/containers.conf
+        # Scope the dns_servers check to the [containers] section only
+        if awk '/^\[containers\]/{f=1;next} /^\[/{f=0} f && /^dns_servers/{found=1} END{exit !found}' \
+                /etc/containers/containers.conf; then
+            # Replace dns_servers only within [containers]
+            awk -v "val=dns_servers = [${_toml_list}]" \
+                '/^\[containers\]/{s=1} /^\[/ && !/^\[containers\]/{s=0}
+                 s && /^dns_servers/{$0=val} 1' \
+                /etc/containers/containers.conf \
+                | sudo tee /etc/containers/containers.conf.tmp > /dev/null \
+                && sudo mv /etc/containers/containers.conf.tmp /etc/containers/containers.conf
         else
             sudo sed -i "/^\[containers\]/a dns_servers = [${_toml_list}]" \
                 /etc/containers/containers.conf