chore: bump chromium to 121.0.6104.0 (main) (#40418)

* chore: bump chromium in DEPS to 121.0.6101.0

* chore: update patches

* Explictly use python3 to check patch diff

* chore: bump chromium in DEPS to 121.0.6102.0

* chore: update patches

* 4995136: [extensions] Enable Extension Mojo messaging

4995136

* Bind the components interfaces to a RenderFrame

4985961
Also:
3986427: Create RendererHost mojom interface for Extensions | 3986427

* 4997024: Enum modernisation for resources_private.idl

4997024

* 4997025: Enum modernisation for scripting.idl

4997025

* chore: bump chromium in DEPS to 121.0.6103.0

* chore: update patches

* chore: bump chromium in DEPS to 121.0.6104.0

* chore: update patches

---------

Co-authored-by: electron-roller[bot] <84116207+electron-roller[bot]@users.noreply.github.com>
Co-authored-by: John Kleinschmidt <jkleinsc@electronjs.org>
Co-authored-by: PatchUp <73610968+patchup[bot]@users.noreply.github.com>

patches/chromium/support_mixed_sandbox_with_zygote.patch

@@ -22,7 +22,7 @@ However, the patch would need to be reviewed by the security team, as it
 does touch a security-sensitive class.
 
 diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
-index 1d9b5d3134c363c7b55bee1cb45a45d3557020e2..179b9a06569a038e95a44ca42e35bf368860f51e 100644
+index 89b1840e1667e51fc5fb7776f2d4d84d0c2b6de9..f259d42038ec740f1aed32f833f258aa724642d7 100644
 --- a/content/browser/renderer_host/render_process_host_impl.cc
 +++ b/content/browser/renderer_host/render_process_host_impl.cc
 @@ -1715,9 +1715,15 @@ bool RenderProcessHostImpl::Init() {