Move ui_devtools tracing dep into public_deps

ui_devtools/connector_delegate.h #include-s
perfetto_service.mojom.h. This means that whoever
includes connector_delegate.h needs to be able to
include perfetto_service.mojom.h. In turn this means
that the dependency on tracing needs to be in public_deps
not just in deps.
Concretely this is preventing to switch some of the objects
that the mojo typemap refers to into compile-time generated
files (the CL that is doing so is [1]), because the targets
that depend on ui_devtools don't see the transitive dep
required by the header.
This fixes it (tested by manually rolling [1] into chrome).

[1] https://android-review.googlesource.com/c/platform/external/perfetto/+/1106801

Bug: 1006776
Bug: b/132880619
Change-Id: Ic5d3cccd9bce3b77ebea69259cbe7e415d963b12
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1863791
Auto-Submit: Primiano Tucci <primiano@chromium.org>
Reviewed-by: Wei Li <weili@chromium.org>
Commit-Queue: Primiano Tucci <primiano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706369}

components/ui_devtools/BUILD.gn

@@ -113,8 +113,6 @@ component("ui_devtools") {
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/system",
     "//net",
-    "//services/tracing/public/cpp",
-    "//services/tracing/public/mojom",
     "//ui/gfx",
   ]
 
@@ -123,6 +121,8 @@ component("ui_devtools") {
     "//services/network/public/cpp",
     "//services/network/public/mojom",
     "//services/service_manager/public/cpp",
+    "//services/tracing/public/cpp",
+    "//services/tracing/public/mojom",
     "//third_party/perfetto/gn:default_deps",
   ]
 }