Add description to THROW_SECURITY_EXCEPTIONS

Having a change id without a description will fail m offline-sdk-docs
once https://android-review.googlesource.com/q/topic:%22compatdocs%22
is merged.
The description is based on the comment on rethrowSecurityException.

Test: m offline-sdk-docs
Bug: 144927670

Change-Id: I49af09b92432f823b10967b02b81f5d8e0ffd593