Fix Select value/selected React warning

Summary:
React outputs the following error:
  Warning: Use the `defaultValue` or `value` props on <select> instead of setting `selected` on <option>.

This fixes it by using value instead of selected.

Reviewed By: danielbuechele

Differential Revision: D15535717

fbshipit-source-id: eb784ba2cdefe1c6744cc15592cd3e0191d237d0

src/plugins/databases/index.js

@@ -698,7 +698,9 @@ export default class DatabasesPlugin extends FlipperPlugin<
                 obj[item] = item;
                 return obj;
               }, {})}
-            selected={String(this.state.selectedDatabase)}
+            selected={
+              this.state.databases[this.state.selectedDatabase - 1]?.name
+            }
             onChange={this.onDatabaseSelected}
           />
           <BoldSpan style={{marginLeft: 16, marginRight: 16}}>Table</BoldSpan>