added permission for WRITE_SETTINGS

[SaumiaSinghal]

Closes #238

What has been done to verify that this works as intended?

I tested it on Android P, and on Android M.

Why is this the best possible solution? Were any other approaches considered?

I added a check for the WRITE_SETTINGS runtime permission, before sending the form.

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

There are no such regression risks, as of now.

Before submitting this PR, please make sure you have:

• [x] run ./gradlew checkCode and confirmed all checks still pass OR confirm CircleCI build passes
• [x] verified that any code or assets from external sources are properly credited in comments and/or in the about file.

[SaumiaSinghal]

Thanks @Chromicle for pointing it out. I somehow missed that:(