clients: cbc_proxy invokes hardcoded function

right now we are doing an end-to-end journey with a CBC from Notify (the
CBE) and we would like to approve a broadcast in notify and have it
appear on our test handset

in order to do this, we:
* hook up the lambda that we made in the correct VPC to cbc_proxy client
* test that it is called correctly

Signed-off-by: Toby Lorne <toby.lornewelch-richards@digital.cabinet-office.gov.uk>
Co-authored-by: Pea <pea.tyczynska@digital.cabinet-office.gov.uk>
Co-authored-by: Katie <katie.smith@digital.cabinet-office.gov.uk>

app/clients/cbc_proxy.py

@@ -1,3 +1,5 @@
+import json
+
 import boto3
 
 # Noop = no operation
@@ -44,9 +46,17 @@ class CBCProxyClient:
         self,
         identifier, headline, description,
     ):
-        # identifier=broadcast_message.identifier,
-        # headline="GOV.UK Notify Broadcast",
-        # description=broadcast_message.description,
+        payload_bytes = bytes(json.dumps({
+            'identifier': identifier,
+            'headline': headline,
+            'description': description,
+        }), encoding='utf8')
+
+        self._ld_client.invoke(
+            FunctionName='bt-ee-1-proxy',
+            InvocationType='RequestResponse',
+            Payload=payload_bytes,
+        )
         pass
 
     # We have not implementated updating a broadcast