Update the security_training_promo_banner.vue to use the shared security_training_promo.vue component

Update the security_training_promo_banner.vue to use the shared security_training_promo.vue component. (And update related specs)

# security_training_promo_banner.vue
# High level pseudo code
<security-training-promo>
  <gl-banner>vulnerability page training promo banner UI</gl-banner>
</security-training-promo>

Please see this implementation plan for details > #373025 (closed)