chore: ensure aws4 is present for mongodb-aws tests

Author: mbroadst

.evergreen/run-mongodb-aws-ecs-test.sh

@@ -16,4 +16,5 @@ export NVM_DIR="${PROJECT_DIRECTORY}/node-artifacts/nvm"
 set -x
 
 # run the tests
+npm install aws4 
 MONGODB_URI=$MONGODB_URI MONGODB_UNIFIED_TOPOLOGY=1 npx mocha test/functional/mongodb_aws.test.js

.evergreen/run-mongodb-aws-test.sh

@@ -21,4 +21,5 @@ shopt -s expand_aliases # needed for `urlencode` alias
 # revert to show test output
 set -x
 
+npm install aws4
 MONGODB_UNIFIED_TOPOLOGY=1 npx mocha test/functional/mongodb_aws.test.js