fix(agent): remove agent updater container instead of stopping it

This commit resolves an issue where the updater container was stopping
itself, preventing its removal after the update process. The previous
implementation of the `CompleteUpdate` method would stop the updater
container, resulting in it remaining in a stopped state rather than
being properly removed.

This behavior led to wasted system resources, as accumulated stopped
containers could complicate the environment. By directly removing the
updater container, we enhance resource management and streamline the
update process.

Author: henrybarreto

pkg/agent/pkg/selfupdater/updater_docker.go

@@ -81,6 +81,10 @@ func (d *dockerUpdater) CompleteUpdate() error {
 		return err
 	}
 
+	if err := d.removeContainer(parent); err != nil {
+		return err
+	}
+
 	_, pv := parent.splitImageVersion()
 	v, _ := semver.NewVersion(pv)
 	v0_4_0, _ := semver.NewVersion("v0.4.0")
@@ -135,7 +139,7 @@ func (d *dockerUpdater) CompleteUpdate() error {
 		return err
 	}
 
-	if err := d.stopContainer(container); err != nil {
+	if err := d.removeContainer(container); err != nil {
 		return err
 	}
 
@@ -179,10 +183,14 @@ func (d *dockerUpdater) stopContainer(container *dockerContainer) error {
 		return err
 	}
 
-	opts := containertypes.RemoveOptions{Force: true, RemoveVolumes: true}
-	err := d.api.ContainerRemove(ctx, container.info.ID, opts)
+	return nil
+}
 
-	return err
+func (d *dockerUpdater) removeContainer(container *dockerContainer) error {
+	ctx := context.Background()
+
+	opts := containertypes.RemoveOptions{Force: true, RemoveVolumes: true}
+	return d.api.ContainerRemove(ctx, container.info.ID, opts)
 }
 
 func (d *dockerUpdater) updateContainer(container *dockerContainer, image, name string, parent bool) (*dockerContainer, error) { //nolint:unparam