refactor(profile): drop extended-profile editing, keep right-panel display

Extended-profile fields (io.element.profile.*) are no longer edited in the
client, so remove the edit form and the dead code that came with it, keeping
only the read-only right-panel display (UserExtendedProfileInfo).

- Remove ExtendedProfileSettings (edit form) + its Settings integration and CSS
- Remove ExtendedProfileView (never-rendered, dead) + its CSS
- Inline the EXT_PROFILE_KEY_* constants into UserExtendedProfileInfo so it no
  longer depends on the deleted settings component
- Drop now-unused set/deleteExtendedProfileProperty from UserProfilesStore
- Prune dead settings|extended_profile_settings|* i18n keys (and the unused
  user_info.extended_profile header/not_provided keys) across all locales
- Regenerate _components.pcss
- Revert UserProfileSettings/AccountUserSettingsTab tests (+snapshot) to master,
  since their adaptations existed only for the removed edit form

apps/web/res/css/views/settings/_ExtendedProfileSettings.pcss

@@ -1,76 +0,0 @@
-.mx_ExtendedProfileSettings {
-    margin-top: 24px;
-    margin-bottom: 16px;
-}
-
-.mx_ExtendedProfileSettings h3 {
-    font-size: 16px;
-    font-weight: 600;
-    margin-top: 0;
-    margin-bottom: 16px;
-}
-
-.mx_ExtendedProfileSettings_fields {
-    display: flex;
-    flex-direction: column;
-    gap: 16px;
-}
-
-.mx_ExtendedProfileSettings_field {
-    width: 100%;
-    margin-bottom: 20px;
-}
-
-.mx_ExtendedProfileSettings_fieldsRow {
-    display: flex;
-    gap: 16px;
-    margin-bottom: 20px;
-    
-    .mx_ExtendedProfileSettings_field {
-        flex: 1;
-        margin-bottom: 0;
-    }
-}
-
-/* Business contact field specific layouts */
-.mx_ExtendedProfileSettings_address_row {
-    .mx_ExtendedProfileSettings_field_business_street {
-        flex: 1;
-    }
-    
-    .mx_ExtendedProfileSettings_field_business_street_nr {
-        flex: 1;
-    }
-}
-
-.mx_ExtendedProfileSettings_postal_row {
-    .mx_ExtendedProfileSettings_field_business_plz {
-        flex: 1;
-    }
-    
-    .mx_ExtendedProfileSettings_field_business_city {
-        flex: 1;
-    }
-}
-
-.mx_ExtendedProfileSettings_contact_row {
-    .mx_ExtendedProfileSettings_field_business_email {
-        flex: 1;
-    }
-    
-    .mx_ExtendedProfileSettings_field_business_tel {
-        flex: 1;
-    }
-}
-
-.mx_ExtendedProfileSettings_buttons {
-    display: flex;
-    gap: 8px;
-    justify-content: flex-end;
-    margin-top: 8px;
-}
-
-.mx_ExtendedProfileSettings_multiline textarea {
-    min-height: 200px;
-    resize: vertical;
-}