Fix template problems with gr-confirm-delete-comment-dialog

Change-Id: I43e00c24ace54f87a5452351eeb43810f78a618a

polygerrit-ui/app/BUILD

diff --git a/polygerrit-ui/app/BUILD b/polygerrit-ui/app/BUILD
index 5f9c3c5..d685bab 100644
--- a/polygerrit-ui/app/BUILD
+++ b/polygerrit-ui/app/BUILD
@@ -121,7 +121,6 @@
     "elements/shared/gr-autocomplete/gr-autocomplete_html.ts",
     "elements/shared/gr-comment-thread/gr-comment-thread_html.ts",
     "elements/shared/gr-comment/gr-comment_html.ts",
-    "elements/shared/gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog_html.ts",
     "elements/shared/gr-dialog/gr-dialog_html.ts",
     "elements/shared/gr-diff-preferences/gr-diff-preferences_html.ts",
     "elements/shared/gr-download-commands/gr-download-commands_html.ts",

polygerrit-ui/app/elements/shared/gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog.ts

diff --git a/polygerrit-ui/app/elements/shared/gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog.ts b/polygerrit-ui/app/elements/shared/gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog.ts
index 0f071abb..0a9b9c3 100644
--- a/polygerrit-ui/app/elements/shared/gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog.ts
+++ b/polygerrit-ui/app/elements/shared/gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog.ts
@@ -54,13 +54,13 @@
    */
 
   @property({type: String})
-  message?: string;
+  message = '';
 
   resetFocus() {
     this.$.messageInput.textarea.focus();
   }
 
-  _handleConfirmTap(e: MouseEvent) {
+  _handleConfirmTap(e: Event) {
     e.preventDefault();
     e.stopPropagation();
     this.dispatchEvent(
@@ -72,7 +72,7 @@
     );
   }
 
-  _handleCancelTap(e: MouseEvent) {
+  _handleCancelTap(e: Event) {
     e.preventDefault();
     e.stopPropagation();
     this.dispatchEvent(