gr-main-header: Show ellipsis when parts of the title text is hidden

Release-Notes: skip
Change-Id: Ibffa6f5b9b72ee5f3281c0d30475326afcc63323
diff --git a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
index 4e5cd66..3be77db 100644
--- a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
+++ b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
@@ -305,6 +305,10 @@
             var(--header-title-content)
           );
           white-space: nowrap;
+          text-overflow: ellipsis;
+          flex: 1;
+          overflow: hidden;
+          min-width: 0;
         }
 
         .linksTitle {
@@ -471,7 +475,7 @@
           }
           .mobileTitle {
             position: relative;
-            display: flex;
+            display: block;
             top: 10px;
             font-size: 20px;
             left: 100px;