[cleanup] Remove `ActionDelegate` singletons.

The `ActionDelegate` implementation singletons don't serve any specific
purpose: These instances are extremely cheap to instantiate (much
cheaper than the singleton bookkeeping actually) and don't have any
meaningful identities that would require the use of the singleton
pattern here. But instead it just adds clutter to the code base, which
we can completely avoid.

Bug: chromium:1379221
Change-Id: If298cf8e3c9f27f60325cd88a476251de5bd4b14
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/5057777
Auto-Submit: Benedikt Meurer <[email protected]>
Reviewed-by: Alex Rudenko <[email protected]>
Commit-Queue: Alex Rudenko <[email protected]>
Commit-Queue: Benedikt Meurer <[email protected]>
diff --git a/front_end/ui/legacy/ActionRegistration.ts b/front_end/ui/legacy/ActionRegistration.ts
index 342611f..76d96c2 100644
--- a/front_end/ui/legacy/ActionRegistration.ts
+++ b/front_end/ui/legacy/ActionRegistration.ts
@@ -457,7 +457,7 @@
    *   <...>
    *    async loadActionDelegate() {
    *      const Elements = await loadElementsModule();
-   *      return Elements.ElementsPanel.ElementsActionDelegate.instance();
+   *      return new Elements.ElementsPanel.ElementsActionDelegate();
    *    },
    *   <...>
    *  });