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/album-page/share-info-modal.svelte

@@ -121,7 +121,8 @@
 
 {#if selectedRemoveUser && selectedRemoveUser?.id === currentUser?.id}
   <ConfirmDialogue
-    title="Leave Album?"
+    id="leave-album-modal"
+    title="Leave album?"
     prompt="Are you sure you want to leave {album.albumName}?"
     confirmText="Leave"
     onConfirm={handleRemoveUser}
@@ -131,7 +132,8 @@
 
 {#if selectedRemoveUser && selectedRemoveUser?.id !== currentUser?.id}
   <ConfirmDialogue
-    title="Remove User?"
+    id="remove-user-modal"
+    title="Remove user?"
     prompt="Are you sure you want to remove {selectedRemoveUser.name}"
     confirmText="Remove"
     onConfirm={handleRemoveUser}