Revert link existing but better 🪦

[chris-hut]

Description

Now that we're removing all of the link existing but better (#20732), let's remove all of this code, to hopefully leave the campground a bit cleaner than it would've been!

I've decided to not backport this to 1.18.X - as that branch can live on with everything hardcoded off, but would prefer to clean up main. Happy to discuss though, and possibly backport this there if needed!

Testing & Reproduction steps

The majority of this feature had entry points on the Services tab, so check there for any mention of Linking a cluster, ideally should look like:

Date	Pr	Reverted
Feb 21st	[Add alert to link to HCP modal] (#20682)	✅
Feb 15th	Change cluster name param to datacenter.name	✅
Feb 13th	Add info error message when acls disabled	✅
Feb 9th	Link to HCP Modal	✅
Feb 1st	Add nav bar item to show HCP link status	✅
Jan 29th	Hide the HCP Link Banner behind env variable	❌
Jan 29th	Fix UI Tests	❌
Jan 26th	Convert Consul HCP to simpler component	❌
Jan 26th	HCP Link status api	✅
Jan 23rd	Purple Banner	✅

The three PRs I haven't reverted here are because:

• Hide the HCP Link Banner behind env was reverted previously
• Fix UI Tests - the tests are removed 🤔
• Conver Consul HCP to simpler component - this is a nice cleanup we'll still want

References

[valeriia-ruban]

Love the description! 😍
Massive work, tested locally and it looks good for me!