Add short delay to treating a 400 as a success to avoid hammering in a loop.
Add short delay to treating a 400 as a success to avoid hammering in a loop.

matrix-org/matrix-js-sdk,williamboman/matrix-js-sdk,matrix-org/matrix-js-sdk,krombel/matrix-js-sdk,krombel/matrix-js-sdk,williamboman/matrix-js-sdk,williamboman/matrix-js-sdk,matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk,krombel/matrix-js-sdk