Add new "Disabled feature" within Mobile app settings for the new Reports option introduced in 4.0

Test

1. Go to Site administration ► Advanced feature and enable "Enable web services for mobile devices"
2. Create a WS Token for one user on the site:
   • Click on Site administration ► Plugins ► Web services ► Manage tokens
3. Go to Site administration ►Mobile app ►Mobile features - Disabled features option
4. Select the "Report builder" option under the Mobile features section
5. Next, you can do a CURL REST call simulating a WS client with the user token.
6. You need to replace the $wstoken and the MOODLE_URL of your moodle instance

   curl 'MOODLE_URL/webservice/rest/server.php?moodlewsrestformat=json' --data 'wsfunction=tool_mobile_get_config&wstoken=$wstoken' --compressed

1. Check that in the WS response, in the tool_mobile_disabledfeatures value field, you see the following value: "CoreReportBuilderDelegate"
2. Now, go back to: Site administration ►Mobile app ►Mobile features - Disabled features option, and unselect "Report builder" option under the Mobile features section
3. Execute the CURL request again and check that the tool_mobile_disabledfeatures value is empty