Update setNullCipherAndIntegrityEnabled AIDL Docs

Specify that integrity protection for user data is optional

Bug: 237529943
Test: N/A docstring
Change-Id: Ifde9da07462ba14f55fb0c0f73935373bb4ba8b7
diff --git a/radio/aidl/android/hardware/radio/network/IRadioNetwork.aidl b/radio/aidl/android/hardware/radio/network/IRadioNetwork.aidl
index 6cd0339..70427f8 100644
--- a/radio/aidl/android/hardware/radio/network/IRadioNetwork.aidl
+++ b/radio/aidl/android/hardware/radio/network/IRadioNetwork.aidl
@@ -488,7 +488,11 @@
     /**
      * Set if null encryption and integrity modes are enabled. If the value of enabled is false
      * the modem must not allow any network communications with null ciphering or null integrity
-     * modes. In case of an emergency call, the modem must bypass this setting.
+     * modes.
+     *
+     * In the case when enabled is false, integrity protection for user data is optional, but
+     * ciphering for user data is required. In case of an emergency call, the modem must bypass
+     * this setting.
      *
      * Null ciphering and integrity modes include (but are not limited to):
      * 2G: A5/0