Adds option to not support hold during IMS calls

Adds a key for not supporting hold during incoming and outgoing IMS
calls. This removes the CAPABILITY_HOLD and CAPABILITY_SUPPORT_HOLD
capabilities from the Connection.

Bug: 30195356
Change-Id: I572aa7cdb80d3b4fdb42ea83f828edac5c75ecd9
diff --git a/assets/carrier_config_311480.xml b/assets/carrier_config_311480.xml
index 4861755..e542557 100644
--- a/assets/carrier_config_311480.xml
+++ b/assets/carrier_config_311480.xml
@@ -1,6 +1,7 @@
 <?xml version='1.0' encoding='utf-8' standalone='yes' ?>
 <carrier_config_list>
     <carrier_config>
+        <boolean name="allow_hold_in_ims_call" value="false" />
         <boolean name="carrier_vt_available_bool" value="true" />
         <boolean name="carrier_allow_turnoff_ims_bool" value="false" />
         <boolean name="carrier_volte_provisioning_required_bool" value="true" />