limit TelecomManager#registerPhoneAccount to 10; api doc update

bug: 209814693
Bug: 217934478
Test: CTS
Change-Id: I8e4425a4e7de716f86b1f1f56ea605d93f357a57
Merged-In: I8e4425a4e7de716f86b1f1f56ea605d93f357a57
1 file changed