feat(web,a11y): standardize the FullScreenModal UI (#8566)

* feat(web,a11y): standardize the FullScreenModal look

* consistent header, padding, close button, and radius as BaseModal
* vertically stacking ConfirmDialogue CTA buttons in narrow screens
* adding aria-modal tags for screen reader
* add viewport-specific height limits on modals, to enable scrolling
* prevent focus from being hidden under sticky content in modals
* standardize FullScreenModal widths using a Prop

* wip: consistent padding with header

* fix: alignment on "create user" and "edit user" modals

* fix: horizontal modal content alignment

* fix: create user CTA buttons

* chore: remove unnecessary warning

---------

Co-authored-by: Jason Rasmussen <jrasm91@gmail.com>

web/src/lib/components/admin-page/delete-confirm-dialogue.svelte

@@ -42,7 +42,8 @@
 </script>
 
 <ConfirmDialogue
-  title="Delete User"
+  id="delete-user-confirmation-modal"
+  title="Delete user"
   confirmText={forceDelete ? 'Permanently Delete' : 'Delete'}
   onConfirm={handleDeleteUser}
   onClose={() => dispatch('cancel')}

web/src/lib/components/admin-page/jobs/jobs-panel.svelte

@@ -147,6 +147,7 @@
 
 {#if confirmJob}
   <ConfirmDialogue
+    id="reprocess-faces-modal"
     prompt="Are you sure you want to reprocess all faces? This will also clear named people."
     {onConfirm}
     onClose={() => (confirmJob = null)}

web/src/lib/components/admin-page/restore-dialogue.svelte

@@ -28,7 +28,8 @@
 </script>
 
 <ConfirmDialogue
-  title="Restore User"
+  id="restore-user-modal"
+  title="Restore user"
   confirmText="Continue"
   confirmColor="green"
   onConfirm={handleRestoreUser}

web/src/lib/components/admin-page/settings/confirm-disable-login.svelte

@@ -5,7 +5,7 @@
   export let onConfirm: () => void;
 </script>
 
-<ConfirmDialogue title="Disable Login" onClose={onCancel} {onConfirm}>
+<ConfirmDialogue id="disable-login-modal" title="Disable login" onClose={onCancel} {onConfirm}>
   <svelte:fragment slot="prompt">
     <div class="flex flex-col gap-4">
       <p>Are you sure you want to disable all login methods? Login will be completely disabled.</p>