Inject model into ToolbarController

To solve crbug.com/359863838, we'll make the ToolbarController [1] observe the PinnedToolbarActionsModel [2]. "OnActionsChanged", the ToolbarController will reorder the responsive_elements_ so that the ActionIds are always properly sorted.

This CL is no-op on its own because it's only doing the required plumbing for the PinnedToolbarActionsModel to be passed to the constructor. On follow-up CLs, I'll actually use that model to make the ToolbarController observe it and re-order the responsive_elements when needed.

[1] https://source.chromium.org/chromium/chromium/src/+/main:chrome/browser/ui/views/toolbar/toolbar_controller.h;l=119;drc=89f0fbf01198959eb2dc66fd26f2fa1753eb526e

[2] https://source.chromium.org/chromium/chromium/src/+/main:chrome/browser/ui/toolbar/pinned_toolbar/pinned_toolbar_actions_model.h;l=22;drc=7ada3acfe99856f4da3531d71e33672bbb8c3a60

Bug: 359863838
Change-Id: Idb5bbc837bb3e88aadf8c4c24086f3dc36ba183c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6039195
Reviewed-by: David Pennington <dpenning@chromium.org>
Commit-Queue: André Bianchessi <abianchessi@chromium.org>
Reviewed-by: Caroline Rising <corising@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1390419}