Update IconButton colors (#30124)

* chore: update `@vector-im/compound-web` to 8.0.0

* refactor(IconButton): use `kind="secondary"` instead of `subtleBackground` props

* test: update snapshots

* fix: force color on room header toggle

* fix: TAC button color

* test(e2e): update release announcement screenshot

test/unit-tests/components/structures/__snapshots__/FilePanel-test.tsx.snap

@@ -20,7 +20,8 @@ exports[`FilePanel renders empty state 1`] = `
       </div>
       <button
         aria-labelledby="«r0»"
-        class="_icon-button_m2erp_8 _subtle-bg_m2erp_29"
+        class="_icon-button_1pz9o_8"
+        data-kind="secondary"
         data-testid="base-card-close-button"
         role="button"
         style="--cpd-icon-button-size: 28px;"