Bump @aws-sdk/client-sns from 3.981.0 to 3.984.0

Bumps [@aws-sdk/client-sns](https://github.com/aws/aws-sdk-js-v3/tree/HEAD/clients/client-sns) from 3.981.0 to 3.984.0.
- [Release notes](https://github.com/aws/aws-sdk-js-v3/releases)
- [Changelog](https://github.com/aws/aws-sdk-js-v3/blob/main/clients/client-sns/CHANGELOG.md)
- [Commits](https://github.com/aws/aws-sdk-js-v3/commits/v3.984.0/clients/client-sns)

---
updated-dependencies:
- dependency-name: "@aws-sdk/client-sns"
  dependency-version: 3.984.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

lambdas/letter-updates-transformer/package.json

@@ -1,6 +1,6 @@
 {
   "dependencies": {
-    "@aws-sdk/client-sns": "^3.943.0",
+    "@aws-sdk/client-sns": "^3.984.0",
     "@aws-sdk/util-dynamodb": "^3.943.0",
     "@internal/datastore": "^0.1.0",
     "@internal/helpers": "^0.1.0",

lambdas/mi-updates-transformer/package.json

@@ -1,6 +1,6 @@
 {
   "dependencies": {
-    "@aws-sdk/client-sns": "^3.954.0",
+    "@aws-sdk/client-sns": "^3.984.0",
     "@aws-sdk/util-dynamodb": "^3.943.0",
     "@internal/datastore": "^0.1.0",
     "@nhsdigital/nhs-notify-event-schemas-supplier-api": "*",