[Impeller] use specific format for bootstrap texture. - #51082

[Impeller] use specific format for bootstrap texture.#51082

auto-submit[bot] merged 2 commits into

flutter-team-archive:mainflutter-team-archive/engine:mainfrom

jonahwilliams:remove_framebuffer_onlyjonahwilliams/engine:remove_framebuffer_onlyCopy head branch name to clipboard