Fix(oncallschedules): update rotation form submission validation

Update rotation form to not a
illow submission if fields are
empty due to blur validation handler

app/assets/stylesheets/page_bundles/oncall_schedules.scss

@@ -37,11 +37,6 @@
   &.gl-modal .modal-md {
     max-width: 640px;
   }
-
-  .dropdown-menu {
-    max-height: $dropdown-max-height;
-    @include gl-overflow-y-auto;
-  }
 }
 
 //// Copied from roadmaps.scss - adapted for on-call schedules

ee/app/assets/javascripts/oncall_schedules/components/rotations/components/add_edit_rotation_form.vue

@@ -137,6 +137,7 @@ export default {
           :dropdown-items="participants"
           :loading="isLoading"
           container-class="gl-h-13! gl-overflow-y-auto"
+          menu-class="gl-overflow-y-auto"
           @text-input="$emit('filter-participants', $event)"
           @blur="$emit('update-rotation-form', { type: 'participants', value: participantsArr })"
           @input="$emit('update-rotation-form', { type: 'participants', value: participantsArr })"

ee/app/assets/javascripts/oncall_schedules/components/rotations/components/add_edit_rotation_modal.vue

@@ -111,6 +111,19 @@ export default {
         },
       };
     },
+    canFormSubmit() {
+      return (
+        isNameFieldValid(this.form.name) &&
+        this.form.participants.length > 0 &&
+        Boolean(this.form.startsAt.date)
+      );
+    },
+    isFormValid() {
+      return Object.values(this.validationState).every(Boolean) && this.canFormSubmit;
+    },
+    isLoading() {
+      return this.loading || this.$apollo.queries.participants.loading;
+    },
     rotationVariables() {
       const {
         name,
@@ -134,12 +147,6 @@ export default {
         participants: getParticipantsForSave(participants),
       };
     },
-    isFormValid() {
-      return Object.values(this.validationState).every(Boolean);
-    },
-    isLoading() {
-      return this.loading || this.$apollo.queries.participants.loading;
-    },
     title() {
       return this.isEditMode ? this.$options.i18n.editRotation : this.$options.i18n.addRotation;
     },