Fix context control components after being broken after navigation

Change 352014 had fixed a bunch of problems already that were happening
when gr-diff disconnects and then re-connects. But unfortunately one
`init()` call is still missing in gr-diff `connectedCallback()`.

This was tested to fix the referenced issue: When going back and forth
between file and change pages the context controls keep working.

Release-Notes: skip
Google-Bug-Id: b/260220322
Change-Id: I18cd233e805a50aa8225370e4ed2b7263fdf18e9
diff --git a/polygerrit-ui/app/embed/diff/gr-diff/gr-diff.ts b/polygerrit-ui/app/embed/diff/gr-diff/gr-diff.ts
index a1e514f..569de48 100644
--- a/polygerrit-ui/app/embed/diff/gr-diff/gr-diff.ts
+++ b/polygerrit-ui/app/embed/diff/gr-diff/gr-diff.ts
@@ -1006,6 +1006,7 @@
     if (this.diffTable && this.diffBuilder) {
       this.highlights.init(this.diffTable, this.diffBuilder);
     }
+    this.diffBuilder.init();
   }
 
   override disconnectedCallback() {