fix: Avoid a M_FORBIDDEN response when a user tries to erase their account and profile updates are disabled#19398

jason-famedly wants to merge 2 commits intoelement-hq:developelement-hq/synapse:developfrom

famedly:jason/fix-erasure-when-displayname-change-forbiddenfamedly/synapse-upstreaming:jason/fix-erasure-when-displayname-change-forbiddenCopy head branch name to clipboard