fix(pres_mgmt): remove auth gate from presenter email access link button

A signed-in POC/chair/moderator who has session auth was blocked from
seeing the Email Access Link button because presenter_is_authed includes
auth__kv.session[session_id]. POCs need to help presenters sign in
regardless of their own auth state.

show__email_access_link (staff-only feature toggle) is the correct gate.
No auth gate needed — same pattern as the session POC email button.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/routes/events/[event_id]/(pres_mgmt)/presenter/[presenter_id]/+page.svelte

@@ -262,7 +262,7 @@ let presenter_is_authed = $derived(
                         ></MyClipboard>
                     {/if}
 
-                    {#if pres_mgmt_loc.current.show__email_access_link && $lq__event_presenter_obj?.person_primary_email && ($ae_loc.trusted_access || !presenter_is_authed)}
+                    {#if pres_mgmt_loc.current.show__email_access_link && $lq__event_presenter_obj?.person_primary_email}
                         <button
                             type="button"
                             onclick={() => {