Restrict deleting a fleet to global admins (#50271)

# Checklist for submitter

- [x] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
See [Changes
files](https://github.com/fleetdm/fleet/blob/main/docs/Contributing/guides/committing-changes.md#changes-files)
for more information.
## Testing

- [x] Added/updated automated tests
- [x] QA'd all new/changed functionality manually


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Bug Fixes**
* Restricted fleet deletion to users with global write permissions,
including global administrators and GitOps.
* Corrected team deletion authorization to require global write access.
* Prevented global technicians, team technicians, and observer-level
users from deleting teams.
* Updated authorization behavior to consistently enforce the required
access level.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

changes/restrict-delete-fleet-to-global-admin

@@ -0,0 +1 @@
+* Restricted deleting a fleet to global write permissions (global admin or GitOps), matching the existing restriction on creating one.

ee/server/service/teams.go

@@ -919,7 +919,7 @@ func (svc *Service) ListAvailableTeamsForUser(ctx context.Context, user *fleet.U
 }
 
 func (svc *Service) DeleteTeam(ctx context.Context, teamID uint) error {
-	if err := svc.authz.Authorize(ctx, &fleet.Team{ID: teamID}, fleet.ActionWrite); err != nil {
+	if err := svc.authz.Authorize(ctx, &fleet.Team{}, fleet.ActionWrite); err != nil {
 		return err
 	}
 

server/service/teams_test.go

@@ -232,7 +232,7 @@ func TestTeamAuth(t *testing.T) {
 			checkAuthErr(t, tt.shouldFailRead, err)
 
 			err = svc.DeleteTeam(ctx, 1)
-			checkAuthErr(t, tt.shouldFailTeamWrite, err)
+			checkAuthErr(t, tt.shouldFailGlobalWrite, err)
 
 			_, err = svc.TeamEnrollSecrets(ctx, 1)
 			checkAuthErr(t, tt.shouldFailRead, err)
@@ -246,6 +246,28 @@ func TestTeamAuth(t *testing.T) {
 	}
 }
 
+func TestDeleteTeamRejectsNonAdminNonGitOpsRoles(t *testing.T) {
+	ds := new(mock.Store)
+	license := &fleet.LicenseInfo{Tier: fleet.TierPremium, Expiration: time.Now().Add(24 * time.Hour)}
+	svc, ctx := newTestService(t, ds, nil, nil, &TestServerOpts{License: license, SkipCreateTestUsers: true})
+
+	for _, tt := range []struct {
+		name string
+		user *fleet.User
+	}{
+		{"global technician", &fleet.User{GlobalRole: new(fleet.RoleTechnician)}},
+		{"team technician, belongs to team", &fleet.User{Teams: []fleet.UserTeam{{Team: fleet.Team{ID: 1}, Role: fleet.RoleTechnician}}}},
+		{"global observer_plus", &fleet.User{GlobalRole: new(fleet.RoleObserverPlus)}},
+		{"team observer_plus, belongs to team", &fleet.User{Teams: []fleet.UserTeam{{Team: fleet.Team{ID: 1}, Role: fleet.RoleObserverPlus}}}},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx := viewer.NewContext(ctx, viewer.Viewer{User: tt.user})
+			err := svc.DeleteTeam(ctx, 1)
+			checkAuthErr(t, true, err)
+		})
+	}
+}
+
 // TestGitOpsCannotManageTeamMembers verifies that a team gitops user cannot
 // add or remove team members (including self-promotion to admin).
 func TestGitOpsCannotManageTeamMembers(t *testing.T) {