Remove max tags check

Prefer to let the AWS API enforce its own constraints. If the max number
of tags is exceeded AWS will return an error.

In addition, the check was never being enforced since it as conditional
on an invalid config error.

builtin/logical/aws/path_roles.go

@@ -16,6 +16,7 @@ import (
 	"github.com/aws/aws-sdk-go/aws/arn"
 	"github.com/hashicorp/go-multierror"
 	"github.com/hashicorp/go-secure-stdlib/strutil"
+
 	"github.com/hashicorp/vault/sdk/framework"
 	"github.com/hashicorp/vault/sdk/helper/consts"
 	"github.com/hashicorp/vault/sdk/logical"
@@ -642,10 +643,6 @@ func (r *awsRoleEntry) validate() error {
 
 	if len(r.SessionTags) > 0 && !strutil.StrListContains(r.CredentialTypes, assumedRoleCred) {
 		errors = multierror.Append(errors, fmt.Errorf("cannot supply session_tags when credential_type isn't %s", assumedRoleCred))
-		// https://docs.aws.amazon.com/IAM/latest/UserGuide/id_session-tags.html#id_session-tags_know
-		if len(r.SessionTags) > 50 {
-			errors = multierror.Append(errors, fmt.Errorf("cannot supply more than %d session_tags", 50))
-		}
 	}
 
 	if r.ExternalID != "" && !strutil.StrListContains(r.CredentialTypes, assumedRoleCred) {