Fix the Easter egg invocation gesture nonfunctional.

- Revome selectable attribute from xml file.

Fixes: 149112358
Test: manual
Change-Id: I660d906cd615fa7a6696301b13638ca3e3d8b7d6

res/xml/firmware_version.xml

@@ -26,7 +26,6 @@
         android:key="os_firmware_version"
         android:title="@string/firmware_version"
         android:summary="@string/summary_placeholder"
-        android:selectable="false"
         settings:enableCopying="true"
         settings:controller="com.android.settings.deviceinfo.firmwareversion.FirmwareVersionDetailPreferenceController"/>