refactor: no group list in an account's details, and no Microsoft Graph call for it

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

internal/provider/azure/azure.go

@@ -9,7 +9,6 @@ import (
 	"crypto/x509"
 	"errors"
 	"fmt"
-	"net/http"
 	"regexp"
 	"slices"
 	"strings"
@@ -37,12 +36,11 @@ var objectTypes = []provider.ObjectType{provider.TypeSecret, provider.TypeKey, p
 type Provider struct {
 	id, label string // "" for the single-account defaults
 
-	cred        azcore.TokenCredential
-	opts        options
-	account     *accountDetails // nil for a service principal from AZURE_*
-	graphClient *http.Client    // for Groups; nil for the default
-	subs        *armsubscriptions.Client
-	graph       *armresourcegraph.Client
+	cred    azcore.TokenCredential
+	opts    options
+	account *accountDetails // nil for a service principal from AZURE_*
+	subs    *armsubscriptions.Client
+	graph   *armresourcegraph.Client
 
 	mu      sync.Mutex
 	vaults  map[string]*vaultClients // by vault URL