New change summary UI - fix small A11y issues

* correct id for radio button
* comments chip - remove 'Account avatar' from description, it's
enough to pronounce '2 unresolved'
* fix show all/less button in related changes - when button 'show all'
 is focused and pressed, we cannot create new button for 'show less'
because it will defocus element. We reuse same button, just with
different label and icon.

Change-Id: I29310115583b7c5ac349923d6014dd49f66aaa1a
diff --git a/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts b/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts
index aae8bb6..94324f3d 100644
--- a/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts
@@ -470,7 +470,6 @@
                     html`<gr-avatar
                       .account="${account}"
                       image-size="32"
-                      aria-label="Account avatar"
                     ></gr-avatar>`
                 )}
                 ${countUnresolvedComments} unresolved</gr-summary-chip
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts b/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts
index ec1235e..c75b8c4 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts
@@ -718,16 +718,15 @@
 
     let button: TemplateResult | typeof nothing = nothing;
     if (collapsible) {
-      if (this.showAll) {
-        button = html`<gr-button link="" @click="${this.toggle}"
-          >Show less<iron-icon icon="gr-icons:expand-less"></iron-icon
-        ></gr-button>`;
-      } else {
-        button = html`<gr-button link="" @click="${this.toggle}"
-          >Show all (${this.length})
-          <iron-icon icon="gr-icons:expand-more"></iron-icon
-        ></gr-button>`;
+      let buttonText = 'Show less';
+      let buttonIcon = 'expand-less';
+      if (!this.showAll) {
+        buttonText = `Show all (${this.length})`;
+        buttonIcon = 'expand-more';
       }
+      button = html`<gr-button link="" @click="${this.toggle}"
+        >${buttonText}<iron-icon icon="gr-icons:${buttonIcon}"></iron-icon
+      ></gr-button>`;
     }
 
     return html`<div class="container">${title}${button}</div>
diff --git a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_html.ts b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_html.ts
index 382e17c..f6bd04e 100644
--- a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list_html.ts
@@ -128,7 +128,7 @@
             on-click="_handleAllComments"
             checked="[[_showAllComments(_draftsOnly, unresolvedOnly)]]"
           />
-          <label for="all">
+          <label for="allRadio">
             All ([[_countAllThreads(threads)]])
           </label>
       </template>