Removal free user cap notification dismissal and add promotion

What does this MR do and why?

#393120

• Removes ability to dismiss owner and non-owner notification alerts for free user cap
• Adds promotion text with a link
• Cleans up some dead code
• converts to use Kernel.format

note: changes behind feature flag.

Screenshots or screen recordings

type	before	after
non-owner
owner

How to set up and validate locally

• Setup gdk to simulate SaaS - https://docs.gitlab.com/ee/development/ee_features.html#simulate-a-saas-instance and restart GDK

bin/rails c

ApplicationSetting.first.update(dashboard_limit_enabled: false)
Feature.disable(:free_user_cap)
Feature.disable(:free_user_cap_new_namespaces)
Feature.disable(:preview_free_user_cap)

• Sign in as free user. Create private group and private project inside.
• Add 4 members.

bin/rails c

ApplicationSetting.first.update(dashboard_limit_enabled: true, dashboard_notification_limit: 3, dashboard_limit: 5, dashboard_enforcement_limit: 5)
Feature.enable(:preview_free_user_cap)

• Go to the group info page. Check alert and see it doesn't match this one and is the owner alert.
• Sign out. Sign in as another group member that is not an owner.
• Go to the group info page. Check alert is present, but has wording matching our change here.
• Go to the project info page. Check alert is not present., but has wording matching our change here

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #393120