[ios] Fix the -rpath value for application extension

Refactor in https://crrev.com/c/2498546 incorrectly used the same value
for -rpath for both applications and application extensions. This caused
the CPE extension to fail at runtime to load the ChromeSSOInternal dylib.

Use the correct value for -rpath for the application extension.

Bug: 1147070
Change-Id: Id46a33c99b77e44f1874680a27bb04f56a1f347e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2529111
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825792}

build/config/ios/BUILD.gn

@@ -151,10 +151,10 @@ config("ios_extension_executable_flags") {
   # On "catalyst", the bundle structure is different (uses the same structure
   # as a regular macOS app), so an additional -rpath is required.
   if (target_environment == "catalyst") {
-    ldflags += [ "-Wl,-rpath,@loader_path/../Frameworks" ]
+    ldflags += [ "-Wl,-rpath,@loader_path/../../../../Frameworks" ]
   }
 
-  ldflags += [ "-Wl,-rpath,@executable_path/Frameworks" ]
+  ldflags += [ "-Wl,-rpath,@executable_path/../../Frameworks" ]
 }
 
 config("ios_dynamic_flags") {