fix(webui): extract translation strings for DropZone.vue

Closes #856

komga-webui/src/components/DropZone.vue

@@ -1,6 +1,6 @@
 <template>
   <label class="drop-zone" v-cloak @drop.prevent="dropHandler" @dragover.prevent>
-    <span class="file-input">Choose an image</span> - drag and drop
+    <span class="file-input">{{ $t('common.choose_image') }}</span> - {{ $t('common.drag_drop') }}
     <input ref="input" hidden aria-hidden="true" type="file" accept="image/*" multiple @change="dropHandler">
   </label>
 </template>

komga-webui/src/locales/en.json

@@ -186,6 +186,7 @@
     "books_n": "No book | 1 book | {count} books",
     "books_total": "{count} / {total} books",
     "cancel": "Cancel",
+    "choose_image": "Choose an image",
     "close": "Close",
     "collections": "Collections",
     "create": "Create",
@@ -193,6 +194,7 @@
     "disk_space": "Disk space",
     "dismiss": "Dismiss",
     "download": "Download",
+    "drag_drop": "drag and drop",
     "email": "Email",
     "filename": "Filename",
     "filter_no_matches": "The active filter has no matches",