Fix redirect problem when documents is empty after filtering

frontend/components/containers/annotation/BottomNavigator.vue

@@ -4,7 +4,10 @@
     absolute
     hide-on-scroll
   >
-    <v-btn @click="prevPage">
+    <v-btn
+      :disabled="value===1"
+      @click="prevPage"
+    >
       <span>Prev</span>
       <v-icon>mdi-chevron-left</v-icon>
     </v-btn>
@@ -24,7 +27,10 @@
       <v-icon>mdi-book-open-outline</v-icon>
     </v-btn> -->
 
-    <v-btn @click="nextPage">
+    <v-btn
+      :disabled="value===length || length===0"
+      @click="nextPage"
+    >
       <span>Next</span>
       <v-icon>mdi-chevron-right</v-icon>
     </v-btn>

frontend/components/containers/annotation/Pagination.vue

@@ -43,7 +43,7 @@
       <template v-slot:activator="{ on }">
         <v-btn
           v-shortkey.once="['arrowright']"
-          :disabled="value===length"
+          :disabled="value===length || length===0"
           text
           fab
           small

frontend/layouts/annotation.vue

@@ -162,7 +162,7 @@ export default {
   watch: {
     total() {
       // To validate the range of page variable on reloading the annotation page.
-      if (this.page > this.total) {
+      if (this.total !== 0 && this.page > this.total) {
         this.$router.push({
           path: `/projects/${this.$route.params.id}/`
         })