Fix variable name in DataAdb

A typo in a variable name caused the exception handling to fail.

Bug:
Test: yarn run dev
Change-Id: Id02495fe323bbb7f6ccbb973fbe6091a3d518523
Merged-In: Id02495fe323bbb7f6ccbb973fbe6091a3d518523
diff --git a/tools/winscope/src/DataAdb.vue b/tools/winscope/src/DataAdb.vue
index f7519d1..4809bb6 100644
--- a/tools/winscope/src/DataAdb.vue
+++ b/tools/winscope/src/DataAdb.vue
@@ -228,7 +228,7 @@
             view.$emit('dataReady', view.dataFiles);
           }
         } catch (err) {
-          view.errorText = ex;
+          view.errorText = err;
           view.status = STATES.ERROR;
         }
       }, "arraybuffer")