Backport of Stop referenced jwt providers from being deleted into release/1.16.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #17755 to be assessed for backporting due to the inclusion of the label backport/1.16.

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The person who merged in the original PR is:
@roncodingenthusiast
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merge conflict error: unable to process merge commit: "75e26d338e6229895be3e44fc6542f846d659d12", automatic backport requires rebase workflow

The below text is copied from the body of the original PR.

---

Description

• Intentions can only reference existing jwt providers
• To improve ux this PR limits the deletion of jwt providers that are referenced by intentions

Testing & Reproduction steps

• create a jwt-provider

consul config write jwt-provider.hcl

# jwt-provider.hcl

Kind = "jwt-provider"
Name = "okta"


// Issuer is the entity that must have issued the JWT.
Issuer = "auth0"

JSONWebKeySet = {
    Local = {
      JWKS = "eyJrZXlzIjpbeyJrdHk....."
    }
}

• write an intention

consul config write intention.hcl

# intention.hcl
Kind = "service-intentions"
Name = "redis"

JWT = {
  Providers = [{ Name = "okta" }]
}
Sources = [{
    Name = "*"
    Action = "allow"
}]

• attempt to delete the okta provider

config delete -name "okta" -kind "jwt-provider"

=> Error deleting config entry jwt-provider/okta: Unexpected response code: 500 (cannot delete jwt provider config entry referenced by an intention. Provider name:okta)

• Now delete the intention

consul config delete -name "redis" -kind "service-intentions"

=> Config entry deleted: service-intentions/redis

• try deleting the provider again

consul config delete -name "okta" -kind "jwt-provider"

=> Config entry deleted: jwt-provider/okta

TODO

• potentially add some more tests

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Overview of commits

• d77048f - 301de59 - 436bcda - 75e26d3

[github-team-consul-core-pr-approver]

Auto approved Consul Bot automated PR