Fix table flickering without hiding content

Summary:
Followup of D39772453 (2437aeb3e9)
Fixes https://fb.workplace.com/groups/flippersupport/permalink/1518236858656967/

1. Stop using clientWidth and offsetWidth because they have rounding errors
2. Since step 1 did not resolve the issue entirely (for some weird reason I do not really have the capacity now to investigate - my bet it is a rounding error when you sum up doubles) set offset of the table to "scroll" instead of "auto". As a result, it starts rendering space for the scrollbars all the time, but since Flipper is a dev tool it should be fine

Reviewed By: antonk52

Differential Revision: D41839402

fbshipit-source-id: cf50eb1600b692d3970003fd1b45b953ee45e3df

desktop/flipper-ui-core/src/chrome/plugin-manager/__tests__/__snapshots__/PluginInstaller.node.tsx.snap

@@ -53,7 +53,7 @@ exports[`load PluginInstaller list 1`] = `
       </span>
     </div>
     <div
-      class="css-o1pvkz-View-FlexBox-FlexColumn-Container emab7y20"
+      class="css-bgfc37-View-FlexBox-FlexColumn-Container emab7y20"
       tabindex="0"
     >
       <div
@@ -130,7 +130,6 @@ exports[`load PluginInstaller list 1`] = `
       </div>
       <div
         class="css-p5h61d-View-FlexBox-FlexColumn-Container emab7y20"
-        style="overflow: visible;"
       >
         <div
           class="ant-dropdown-trigger css-18abd42-View-FlexBox-FlexColumn e1e47qlf0"
@@ -440,7 +439,7 @@ exports[`load PluginInstaller list with one plugin installed 1`] = `
       </span>
     </div>
     <div
-      class="css-o1pvkz-View-FlexBox-FlexColumn-Container emab7y20"
+      class="css-bgfc37-View-FlexBox-FlexColumn-Container emab7y20"
       tabindex="0"
     >
       <div
@@ -517,7 +516,6 @@ exports[`load PluginInstaller list with one plugin installed 1`] = `
       </div>
       <div
         class="css-p5h61d-View-FlexBox-FlexColumn-Container emab7y20"
-        style="overflow: visible;"
       >
         <div
           class="ant-dropdown-trigger css-18abd42-View-FlexBox-FlexColumn e1e47qlf0"