Rework modal header structure

src/app/components/KeyRecoveryConfirm.svelte

@@ -12,6 +12,8 @@
   import Modal from "@lib/components/Modal.svelte"
   import ModalBody from "@lib/components/ModalBody.svelte"
   import ModalHeader from "@lib/components/ModalHeader.svelte"
+  import ModalTitle from "@lib/components/ModalTitle.svelte"
+  import ModalSubtitle from "@lib/components/ModalSubtitle.svelte"
   import ModalFooter from "@lib/components/ModalFooter.svelte"
   import KeyDownload from "@app/components/KeyDownload.svelte"
   import {pushToast} from "@app/util/toast"
@@ -86,12 +88,8 @@
 <Modal tag="form" onsubmit={preventDefault(submit)}>
   <ModalBody>
     <ModalHeader>
-      {#snippet title()}
-        Recover your Key
-      {/snippet}
-      {#snippet info()}
-        Take control over your cryptographic identity
-      {/snippet}
+      <ModalTitle>Recover your Key</ModalTitle>
+      <ModalSubtitle>Take control over your cryptographic identity</ModalSubtitle>
     </ModalHeader>
     <p>Your recovery codes have been sent!</p>
     <p>