Fix <br/> being shown verbatim in checks error message

Release-Notes: skip
Google-Bug-Id: b/269635712
Change-Id: I5e4b4aa0eae52b5dde5b6ab2121d7967b960327a
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-runs.ts b/polygerrit-ui/app/elements/checks/gr-checks-runs.ts
index 128a9b0a..8ba9895 100644
--- a/polygerrit-ui/app/elements/checks/gr-checks-runs.ts
+++ b/polygerrit-ui/app/elements/checks/gr-checks-runs.ts
@@ -634,7 +634,7 @@
     return Object.entries(this.errorMessages).map(([plugin, message]) => {
       const msg = this.collapsed
         ? 'Error'
-        : `Error while fetching results for ${plugin}:<br />${message}`;
+        : html`Error while fetching results for ${plugin}:<br />${message}`;
       return html`
         <div class="error">
           <div class="left">
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-runs_test.ts b/polygerrit-ui/app/elements/checks/gr-checks-runs_test.ts
index 4bd3446..a858e4d 100644
--- a/polygerrit-ui/app/elements/checks/gr-checks-runs_test.ts
+++ b/polygerrit-ui/app/elements/checks/gr-checks-runs_test.ts
@@ -22,6 +22,7 @@
     );
     const getChecksModel = resolve(element, checksModelToken);
     setAllFakeRuns(getChecksModel());
+    element.errorMessages = {'test-plugin-name': 'test-error-message'};
     await element.updateComplete;
   });
 
@@ -57,6 +58,17 @@
             </gr-button>
           </gr-tooltip-content>
         </h2>
+        <div class="error">
+          <div class="left">
+            <gr-icon filled="" icon="error"> </gr-icon>
+          </div>
+          <div class="right">
+            <div class="message">
+              Error while fetching results for test-plugin-name: <br />
+              test-error-message
+            </div>
+          </div>
+        </div>
         <input
           id="filterInput"
           placeholder="Filter runs by regular expression"
@@ -121,6 +133,14 @@
             </gr-button>
           </gr-tooltip-content>
         </h2>
+        <div class="error">
+          <div class="left">
+            <gr-icon filled="" icon="error"> </gr-icon>
+          </div>
+          <div class="right">
+            <div class="message">Error</div>
+          </div>
+        </div>
         <input
           hidden
           id="filterInput"