Fix trigger compat test for canton sandbox (#12549)

This fixes the timeout on trigger compat tests for the new sandbox (with LF >= 1.14).

The issue was that the trigger was "readAs"-ing with a party that
doesn't exist, since party ids aren't predictable with the new sandbox.

The solution is to allocate the Alice party ahead of time, and then
pass the allocated party in when calling `daml trigger`.

changelog_begin
changelog_end

compatibility/bazel_tools/daml_trigger/daml_trigger.bzl

@@ -144,10 +144,21 @@ canonicalize_rlocation() {{
 runner=$$(canonicalize_rlocation $(rootpath {runner}))
 # Cleanup the trigger runner process but maintain the script runner exit code.
 trap 'status=$$?; kill -TERM $$PID; wait $$PID; exit $$status' INT TERM
+
+SCRIPTOUTPUT=$$(mktemp -d)
+$$runner script \\
+  --ledger-host localhost \\
+  --ledger-port 6865 \\
+  --wall-clock-time \\
+  --dar $$(canonicalize_rlocation $(rootpath {dar})) \\
+  --script-name TestScript:allocateAlice \\
+  --output-file $$SCRIPTOUTPUT/alice.json
+ALICE=$$(cat $$SCRIPTOUTPUT/alice.json | sed 's/"//g')
+rm -rf $$SCRIPTOUTPUT
 $$runner trigger \\
   --ledger-host localhost \\
   --ledger-port 6865 \\
-  --ledger-party Alice \\
+  --ledger-party $$ALICE \\
   --wall-clock-time \\
   --dar $$(canonicalize_rlocation $(rootpath {dar})) \\
   --trigger-name CopyTrigger:copyTrigger &

compatibility/bazel_tools/daml_trigger/example/src/TestScript.daml

@@ -8,10 +8,24 @@ import DA.Assert
 import DA.Time
 import Daml.Script
 
+allocateAlice : Script Party
+allocateAlice = do
+  debug "Creating Alice ..."
+  alice <- allocatePartyWithHint "Alice" (PartyIdHint "Alice")
+  debug alice
+  debug "... done"
+  pure alice
+
 test : Script ()
 test = do
-  debug "Creating parties ..."
-  alice <- allocatePartyWithHint "Alice" (PartyIdHint "Alice")
+  debug "Searching for Alice ..."
+  let isAlice x = displayName x == Some "Alice"
+  Some aliceDetails <- find isAlice <$> listKnownParties
+  let alice = party aliceDetails
+  debug alice
+  debug "... done"
+
+  debug "Creating Bob ..."
   bob <- allocatePartyWithHint "Bob" (PartyIdHint "Bob")
   debug alice
   debug bob