Update API doc for accidentally exposed NETWORK_TYPE_BITMASK_LTE_CA

NETWORK_TYPE_BITMASK_LTE_CA is not used anywhere even if it's
accidentally passed into setAllowedNetworkTypesForReason(). Will be deprecated in U.

Fix: 230383206
Test: atest cts/tests/tests/telephony/current/src/android/telephony/cts/TelephonyManagerTest.java
Change-Id: Id0c521c4fb74eaf7d73deaf122e923f72b924c18
Merged-In: Id0c521c4fb74eaf7d73deaf122e923f72b924c18