Fixed polymer-template-event-attribute-policy policy violation.

(cherry picked from commit 576a2d9)

Bug: b/259455242, b/259571718
Change-Id: Iaf29b11ad76c834cdaa5e5708da05dfa31426ca3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4032079
Commit-Queue: Li Lin <llin@chromium.org>
Reviewed-by: Xiqi Ruan <xiqiruan@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1073139}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4035150
Cr-Commit-Position: refs/branch-heads/5414@{#147}
Cr-Branched-From: 4417ee5-refs/heads/main@{#1070088}

ash/webui/projector_app/trusted_projector_annotator_ui.cc

@@ -46,6 +46,11 @@ content::WebUIDataSource* CreateProjectorAnnotatorHTMLSource() {
   source->OverrideContentSecurityPolicy(
       network::mojom::CSPDirectiveName::FrameSrc, csp);
 
+  source->OverrideContentSecurityPolicy(
+      network::mojom::CSPDirectiveName::TrustedTypes,
+      "trusted-types polymer-html-literal "
+      "polymer-template-event-attribute-policy;");
+
   return source;
 }