Revert the security exception for voip phone account registration.

In ag/30238448 I modified the security exception text; reverting it back
to what it was to hopefully prevent a CTS test failure (which I did in
ag/30350056 but for some reason still isn't sticking).  :shrug:

Test: Run CTS tests
Flag: com.android.server.telecom.flags.enforce_transactional_exclusivity
Fixes: 378817915
Change-Id: If56767456108b0717ea98611f68f7514c90f3991
diff --git a/src/com/android/server/telecom/TelecomServiceImpl.java b/src/com/android/server/telecom/TelecomServiceImpl.java
index 7ec2687..a662dde 100644
--- a/src/com/android/server/telecom/TelecomServiceImpl.java
+++ b/src/com/android/server/telecom/TelecomServiceImpl.java
@@ -892,8 +892,7 @@
                                             PhoneAccount.CAPABILITY_CONNECTION_MANAGER) ||
                                     account.hasCapabilities(
                                             PhoneAccount.CAPABILITY_SIM_SUBSCRIPTION)) {
-                                throw new SecurityException("Self-managed ConnectionServices and "
-                                        + "transactional voip apps "
+                                throw new SecurityException("Self-managed ConnectionServices "
                                         + "cannot also be call capable, connection managers, or "
                                         + "SIM accounts.");
                             }