[fonts] use fuchsia-pkg URLs

TESTED=
fx shell '/system/test/font_provider_test'

CF-156 #comment

Change-Id: I1e0277c1d9e7fe23f81e1e3ed5bcaf4df5e3c0df
diff --git a/bin/fonts/tests/font_provider_test.rs b/bin/fonts/tests/font_provider_test.rs
index 179abb7..15ac87d 100644
--- a/bin/fonts/tests/font_provider_test.rs
+++ b/bin/fonts/tests/font_provider_test.rs
@@ -56,7 +56,7 @@
 fn start_provider_with_default_fonts() -> Result<(App, fonts::ProviderProxy), Error> {
     let launcher = Launcher::new().context("Failed to open launcher service")?;
     let app = launcher
-        .launch("fonts".to_string(), None)
+        .launch("fuchsia-pkg://fuchsia.com/fonts#meta/fonts.cmx".to_string(), None)
         .context("Failed to launch fonts::Provider")?;
 
     let font_provider = app