Update SubscriptionInfo ICCID docs to reflect security patch behavior

Starting in API level 30 SubscriptionInfo getIccId and getCardString
were protected with the new device identifier access requirements
since these return the same value as TelephonyManager
getSimSerialNumber. However since this value was supposed to be
protected by the new device identifier access requirements in API
level 29 a fix was added to security patch 2021-04-05 to enforce these
new requirements for the SubscriptionInfo ICCID APIs. This commit
updates the documentation for these APIs to reflect these new behavior
on these security patch levels.

Bug: 188770462
Test: m offline-sdk-docs
Change-Id: I17e8deb6515b1272e438be6dcbbecb741bd73641