Disable toggleable service extension buttons while waiting for a response

See "Show Guidelines" and "Highlight Oversize Images" in gif. It is not these two buttons specifically. This is inconsistent and I saw this issue with all these toggle buttons at some point.

CC @alexlindroos

Start by reproducing the inconsistent behavior shown in the attached GIF using the “Show Guidelines” and “Highlight Oversize Images” toggle buttons. Trace the shared handling for toggleable service-extension buttons and identify how pending responses are represented. Done means every such button is disabled while its response is pending and becomes usable again afterward.

Scritto dal modello di indicizzazione a partire dal testo della issue.