fixup! fix(f3): test API during inactive-F3 modes and make consistent…

… and safe

chain/lf3/f3.go

@@ -194,7 +194,7 @@ func (fff *F3) GetManifest(ctx context.Context) (*manifest.Manifest, error) {
 	}
 	cert0, err := fff.inner.GetCert(ctx, 0)
 	if err != nil {
-		return m, xerrors.Errorf("getting certificate for instance 0: %w", err)
+		return m, nil // return manifest without power table
 	}
 
 	var mCopy = *m

itests/f3_test.go

@@ -353,7 +353,9 @@ func (e *testEnv) waitTillF3Instance(i uint64, timeout time.Duration) {
 func (e *testEnv) waitTillManifestChange(newManifest *manifest.Manifest, timeout time.Duration) {
 	e.waitFor(func(n *kit.TestFullNode) bool {
 		m, err := n.F3GetManifest(e.testCtx)
-		require.NoError(e.t, err)
+		if err != nil || m == nil {
+			return false
+		}
 		return newManifest.Equal(m)
 	}, timeout)
 }