Some fixes in rendering legacy plugins

Summary:
Some exploratory testing on all iOS and Android plugins, to see how they behave inside Sandy, and fixed some layout glitches (some were also present without Sandy)

General fixes:
* Introduced some niceties like searchbox resizing properly, and toolbars wrapping automatically in Sandy, rather than buttons becoming invisible
* Containers don't grow anymore by default, but take size of contents
* ScrollContainer child is now a Layout.Vertical. Layout.Vertical should be used as default container everywhere (e.g. Tabs, Panels) in the future
* Fixed layout issue if a split container had only 1 visible child
* DetailsSidebar now scrolls vertically by default
* Details sidebar would sometimes render content in-place rather than in the reserved area
* AppSelector dropdown and Plugin list will now properly ellipse (...) if there is not enough space

Plugin fixes:
* Long database / table names in Database plugin would break layout

Also fixes https://github.com/facebook/flipper/issues/1611

Reviewed By: passy

Differential Revision: D24454188

fbshipit-source-id: c60c867270900a1d4f28587d47067c6ec1072ede

desktop/plugins/network/index.tsx

@@ -531,9 +531,7 @@ export function Component() {
           searchTerm={searchTerm}
           isMockResponseSupported={isMockResponseSupported}
         />
-        <DetailSidebar width={500}>
-          <Sidebar />
-        </DetailSidebar>
+        <Sidebar />
       </NetworkRouteContext.Provider>
     </FlexColumn>
   );
@@ -759,13 +757,15 @@ function Sidebar() {
   }
 
   return (
-    <RequestDetails
-      key={selectedId}
-      request={requestWithId}
-      response={responses[selectedId]}
-      bodyFormat={detailBodyFormat}
-      onSelectFormat={instance.onSelectFormat}
-    />
+    <DetailSidebar width={500}>
+      <RequestDetails
+        key={selectedId}
+        request={requestWithId}
+        response={responses[selectedId]}
+        bodyFormat={detailBodyFormat}
+        onSelectFormat={instance.onSelectFormat}
+      />
+    </DetailSidebar>
   );
 }