Fix css layout issue introduced by lit conversion of gr-account-dropdown

Conversion was done in change 315382.

There are subtle problems with passing properties from Polymer to Lit
and the other way around:

1. When you pass a property in a Lit template then you have to use the
actual camel casing of the property name. The Polymer magic of
converting foo-bar to fooBar implicitly does not happen anymore.

2. When you are using the dot notation for passing properties then you
have to use a ${} value. Otherwise Lit will interpret this verbatim.
So you have to do `.imageSize=${56}` instead of `.imageSize="56"`.

Change-Id: I28a37d2aade495b37ee670d67339fed9d2a5273c
diff --git a/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown.ts b/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown.ts
index 881eb28..4d3511d 100644
--- a/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown.ts
+++ b/polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown.ts
@@ -111,17 +111,17 @@
       <gr-dropdown
         link=""
         .items="${this.links}"
-        .top-content="${this.topContent}"
+        .topContent="${this.topContent}"
         @tap-item-shortcuts=${this._handleShortcutsTap}
-        .horizontal-align="right"
+        .horizontalAlign=${'right'}
       >
-        <span ?hidden=${this._hasAvatars}
+        <span ?hidden="${this._hasAvatars}"
           >${this._accountName(this.account)}</span
         >
         <gr-avatar
           .account="${this.account}"
           ?hidden=${!this._hasAvatars}
-          .imageSize="56"
+          .imageSize=${56}
           aria-label="Account avatar"
         ></gr-avatar>
       </gr-dropdown>`;