fix(DroppableTextArea): add missing style file

tests/ui/modules/Common/Styles/DroppableTextAreaStyle.qml

+pragma Singleton
+import QtQuick 2.7
+
+import Common 1.0
+
+QtObject {
+  property QtObject fileChooserButton: QtObject {
+    property int margins: 6
+    property int width: 40
+  }
+
+  property QtObject hoverContent: QtObject {
+    property color backgroundColor: Colors.k
+
+    property QtObject text: QtObject {
+      property color color: Colors.i
+
+      property int fontSize: 11
+    }
+  }
+}