test(bigtable): increase test context timeout (#5045)

diff --git a/bigtable/integration_test.go b/bigtable/integration_test.go
index 34e3548..6313dd2 100644
--- a/bigtable/integration_test.go
+++ b/bigtable/integration_test.go
@@ -2395,7 +2395,7 @@
 		t.Skip("emulator doesn't support backups")
 	}
 
-	timeout := 5 * time.Minute
+	timeout := 10 * time.Minute
 	ctx, _ := context.WithTimeout(context.Background(), timeout)
 
 	adminClient, err := testEnv.NewAdminClient()