Some clients do not set up key backup automatically, leading to UTDs

[richvdh]

Modern clients (i.e. Element X) set up server-side message key storage (key backup) on login, unless you explicitly opt out.

Other clients (e.g. Element Web, classic mobile clients) do not do this, and then users are surprised when they cannot read history on new devices.

[richvdh]

Related: element-hq/element-web#27952

[mxandreas]

Other clients (e.g. Element Web, classic mobile clients) do not do this, and then users are surprised when they cannot read history on new devices.

We're currently unifying the UX on EW with EX, so eventually there should be a single toggle to turn ON/OFF the key storage. Verify that this fixes or minimizes the issue in here.