ios: Set ios_use_goma_rbe=true in Goma RBE canary builder

Bug: 1044515
Change-Id: I0bb73e38252707e6bc42e8659b3f14d22dd24a61
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2089449
Commit-Queue: Simon Que <sque@chromium.org>
Auto-Submit: Simon Que <sque@chromium.org>
Reviewed-by: Yoshisato Yanagisawa <yyanagisawa@google.com>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747654}

ios/build/bots/chromium.goma.fyi/ios-device-goma-rbe-canary-clobber.json

@@ -7,6 +7,7 @@
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "ios_enable_code_signing=false",
+    "ios_use_goma_rbe=true",
     "is_component_build=false",
     "is_debug=false",
     "symbol_level=0",