[fuchsia] Make extensions_unittests pass

* Add missing manifest fragment for extensions_unittests
* Disable remaining failing tests due to missing platform definition
* Add extensions_unittests to the FYI Fuchsia waterfall

Bug: 1243462, 1243780
Change-Id: I246a35eceb6b8d42df5ff28b4d8c06a48def309f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3123429
Reviewed-by: Reilly Grant <[email protected]>
Reviewed-by: Chong Gu <[email protected]>
Commit-Queue: Fabrice de Gans <[email protected]>
Cr-Commit-Position: refs/heads/main@{#915731}
diff --git a/extensions/BUILD.gn b/extensions/BUILD.gn
index 71c2c8e..b662ede 100644
--- a/extensions/BUILD.gn
+++ b/extensions/BUILD.gn
@@ -255,8 +255,10 @@
   data_deps = [ "//third_party/mesa_headers" ]
 
   if (is_fuchsia) {
-    additional_manifest_fragments =
-        [ "//build/config/fuchsia/test/jit_capabilities.test-cmx" ]
+    additional_manifest_fragments = [
+      "//build/config/fuchsia/test/jit_capabilities.test-cmx",
+      "//build/config/fuchsia/test/network_capabilities.test-cmx",
+    ]
   }
 }