Remove frontend code used in ci_require_credit_card_on_(trial|free)_plan

What does this MR do and why?

Resolves https://gitlab.com/gitlab-org/modelops/anti-abuse/team-tasks/-/issues/763.

This MR cleans up the remaining frontend code used in the already removed ci_require_credit_card_on_trial_plan and ci_require_credit_card_on_free_plan features.

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